Buggy python submission (verdict: Time Limit Exceeded):
from sys import stdin


if __name__ == "__main__":
    #main()

    _in = [_.rstrip() for _ in stdin.readlines()]
    S =     _in[0]   # type:str
    # vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
    len_S = len(S)
    cnt = 0
    mod_arr = [0 for i in range(2019)]
    mod_arr[0] += 1
    for i in range(0,len_S+1):
        _ = int(S[len_S-i-1:])
        if i>0: mod = (mod+int(S[len_S-i-1])*10**i)%2019
        else:   mod = _%2019
        mod_arr[mod]+=1
    for i in range(2019):
        if mod_arr[i] > 0:
            cnt += mod_arr[i]*(mod_arr[i]-1)//2
    # ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    print(cnt)


Fixed submission:
from sys import stdin


def main():
    _in = [_.rstrip() for _ in stdin.readlines()]
    S =     _in[0]   # type:str
    # vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
    len_S = len(S)
    cnt = 0
    for i in range(len_S):
        for j in range(i+3,len_S):
            if j == i+3:
                mod = int(S[len_S-j-1:len_S-i])%3
            else:
                mod = (mod+int(S[len_S-j-1]))%3
            if mod == 0:
                _ = int(S[len_S-j-1:len_S-i])
                if _%673==0:
                    cnt += 1
                    break
    # ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    print(cnt)


if __name__ == "__main__":
    #main()

    _in = [_.rstrip() for _ in stdin.readlines()]
    S =     _in[0]   # type:str
    # vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
    cnt = 0
    mod_arr = [0] * 2019
    mod_arr[0] += 1

    num, dec = 0, 1
    for s in S[::-1]:
        num += int(s)*dec
        num %= 2019
        dec *= 10
        dec %= 2019
        mod_arr[num] += 1

    for i in range(2019):
        if mod_arr[i] > 0:
            cnt += mod_arr[i]*(mod_arr[i]-1)//2
    # ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    print(cnt)

Buggy python submission (verdict: Time Limit Exceeded):
from sys import stdin
from collections import OrderedDict

def main():
    _in = [_.rstrip() for _ in stdin.readlines()]
    S =     _in[0]   # type:str
    # vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
    len_S = len(S)
    cnt = 0
    for i in range(len_S):
        for j in range(i+3,len_S):
            if j == i+3:
                mod = int(S[len_S-j-1:len_S-i])%3
            else:
                mod = (mod+int(S[len_S-j-1]))%3
            if mod == 0:
                _ = int(S[len_S-j-1:len_S-i])
                if _%673==0:
                    cnt += 1
                    break
    # ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    print(cnt)


if __name__ == "__main__":
    #main()

    _in = [_.rstrip() for _ in stdin.readlines()]
    S =     _in[0]   # type:str
    # vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
    len_S = len(S)
    cnt = 0
    mod_arr = OrderedDict()
    for i in range(2019):
        mod_arr[i] = 0
    mod_arr[0] += 1
    for i in range(0,len_S+1):
        _ = int(S[len_S-i-1:])
        if i>0: mod = (mod+int(S[len_S-i-1])*10**i)%2019
        else:   mod = _%2019
        mod_arr[mod]+=1
    for i in range(2019):
        if mod_arr[i] > 0:
            cnt += mod_arr[i]*(mod_arr[i]-1)//2
    # ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    print(cnt)


Fixed submission:
from sys import stdin


def main():
    _in = [_.rstrip() for _ in stdin.readlines()]
    S =     _in[0]   # type:str
    # vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
    len_S = len(S)
    cnt = 0
    for i in range(len_S):
        for j in range(i+3,len_S):
            if j == i+3:
                mod = int(S[len_S-j-1:len_S-i])%3
            else:
                mod = (mod+int(S[len_S-j-1]))%3
            if mod == 0:
                _ = int(S[len_S-j-1:len_S-i])
                if _%673==0:
                    cnt += 1
                    break
    # ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    print(cnt)


if __name__ == "__main__":
    #main()

    _in = [_.rstrip() for _ in stdin.readlines()]
    S =     _in[0]   # type:str
    # vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
    cnt = 0
    mod_arr = [0] * 2019
    mod_arr[0] += 1

    num, dec = 0, 1
    for s in S[::-1]:
        num += int(s)*dec
        num %= 2019
        dec *= 10
        dec %= 2019
        mod_arr[num] += 1

    for i in range(2019):
        if mod_arr[i] > 0:
            cnt += mod_arr[i]*(mod_arr[i]-1)//2
    # ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    print(cnt)

Buggy python submission (verdict: Time Limit Exceeded):
from sys import stdin


def main():
    _in = [_.rstrip() for _ in stdin.readlines()]
    S =     _in[0]   # type:str
    # vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
    len_S = len(S)
    cnt = 0
    for i in range(len_S):
        for j in range(i+3,len_S):
            if j == i+3:
                mod = int(S[len_S-j-1:len_S-i])%3
            else:
                mod = (mod+int(S[len_S-j-1]))%3
            if mod == 0:
                _ = int(S[len_S-j-1:len_S-i])
                if _%673==0:
                    cnt += 1
                    break
    # ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    print(cnt)


def ans():
    _in = [_.rstrip() for _ in stdin.readlines()]
    S =     _in[0]   # type:str
    # vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
    len_S = len(S)
    cnt = 0
    mod_arr = {}
    for i in range(2019):
        mod_arr[i] = 0
    mod_arr[0] += 1
    for i in range(0,len_S+1):
        _ = int(S[len_S-i-1:])
        if i>0: mod = (mod+int(S[len_S-i-1])*10**i)%2019
        else:   mod = _%2019
        mod_arr[mod]+=1
    for i in range(2019):
        if mod_arr[i] > 0:
            cnt += mod_arr[i]*(mod_arr[i]-1)//2
    # ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    print(cnt)


if __name__ == "__main__":
    #main()
    ans()


Fixed submission:
from sys import stdin


def main():
    _in = [_.rstrip() for _ in stdin.readlines()]
    S =     _in[0]   # type:str
    # vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
    len_S = len(S)
    cnt = 0
    for i in range(len_S):
        for j in range(i+3,len_S):
            if j == i+3:
                mod = int(S[len_S-j-1:len_S-i])%3
            else:
                mod = (mod+int(S[len_S-j-1]))%3
            if mod == 0:
                _ = int(S[len_S-j-1:len_S-i])
                if _%673==0:
                    cnt += 1
                    break
    # ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    print(cnt)


if __name__ == "__main__":
    #main()

    _in = [_.rstrip() for _ in stdin.readlines()]
    S =     _in[0]   # type:str
    # vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
    cnt = 0
    mod_arr = [0] * 2019
    mod_arr[0] += 1

    num, dec = 0, 1
    for s in S[::-1]:
        num += int(s)*dec
        num %= 2019
        dec *= 10
        dec %= 2019
        mod_arr[num] += 1

    for i in range(2019):
        if mod_arr[i] > 0:
            cnt += mod_arr[i]*(mod_arr[i]-1)//2
    # ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    print(cnt)

Buggy python submission (verdict: Time Limit Exceeded):
from sys import stdin


def main():
    _in = [_.rstrip() for _ in stdin.readlines()]
    S =     _in[0]   # type:str
    # vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
    len_S = len(S)
    cnt = 0
    for i in range(len_S):
        for j in range(i+3,len_S):
            if j == i+3:
                mod = int(S[len_S-j-1:len_S-i])%3
            else:
                mod = (mod+int(S[len_S-j-1]))%3
            if mod == 0:
                _ = int(S[len_S-j-1:len_S-i])
                if _%673==0:
                    cnt += 1
                    break
    # ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    print(cnt)


def ans():
    _in = [_.rstrip() for _ in stdin.readlines()]
    S =     _in[0]   # type:str
    # vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
    len_S = len(S)
    cnt = 0
    mod_arr = {}
    for i in range(2019):
        mod_arr[i] = 0
    mod_arr[0] += 1
    for i in range(0,len_S+1):
        _ = int(S[len_S-i-1:])
        if i>0: mod = (mod+int(S[len_S-i-1])*10**i)%2019
        else:   mod = _%2019
        mod_arr[mod]+=1
    for i in range(2019):
        if mod_arr[i] > 0:
            cnt += mod_arr[i]*(mod_arr[i]-1)//2
    # ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    print(cnt)


if __name__ == "__main__":
    #main()
    ans()


Fixed submission:
from sys import stdin


def main():
    _in = [_.rstrip() for _ in stdin.readlines()]
    S =     _in[0]   # type:str
    # vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
    len_S = len(S)
    cnt = 0
    for i in range(len_S):
        for j in range(i+3,len_S):
            if j == i+3:
                mod = int(S[len_S-j-1:len_S-i])%3
            else:
                mod = (mod+int(S[len_S-j-1]))%3
            if mod == 0:
                _ = int(S[len_S-j-1:len_S-i])
                if _%673==0:
                    cnt += 1
                    break
    # ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    print(cnt)


if __name__ == "__main__":
    #main()

    _in = [_.rstrip() for _ in stdin.readlines()]
    S =     _in[0]   # type:str
    # vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
    cnt = 0
    mod_arr = [0] * 2019
    mod_arr[0] += 1

    num, dec = 0, 1
    for s in S[::-1]:
        num += int(s)*dec
        num %= 2019
        dec *= 10
        dec %= 2019
        mod_arr[num] += 1

    for i in range(2019):
        if mod_arr[i] > 0:
            cnt += mod_arr[i]*(mod_arr[i]-1)//2
    # ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    print(cnt)

Buggy python submission (verdict: Time Limit Exceeded):
from sys import stdin


def main():
    _in = [_.rstrip() for _ in stdin.readlines()]
    S =     _in[0]   # type:str
    # vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
    len_S = len(S)
    cnt = 0
    for i in range(len_S):
        for j in range(i+3,len_S):
            if j == i+3:
                mod = int(S[len_S-j-1:len_S-i])%3
            else:
                mod = (mod+int(S[len_S-j-1]))%3
            if mod == 0:
                _ = int(S[len_S-j-1:len_S-i])
                if _%673==0:
                    cnt += 1
                    break
    # ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    print(cnt)


def ans():
    _in = [_.rstrip() for _ in stdin.readlines()]
    S =     _in[0]   # type:str
    # vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
    len_S = len(S)
    cnt = 0
    mod_arr = {}
    for i in range(2019):
        mod_arr[i] = 0
    mod_arr[0] += 1
    for i in range(0,len_S+1):
        _ = int(S[len_S-i-1:])
        if i>0: mod = (mod+int(S[len_S-i-1])*10**i)%2019
        else:   mod = _%2019
        mod_arr[mod]+=1
    for value in mod_arr.values():
        if value>1:
            cnt += value*(value-1)//2
    # ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    print(cnt)


if __name__ == "__main__":
    #main()
    ans()


Fixed submission:
from sys import stdin


def main():
    _in = [_.rstrip() for _ in stdin.readlines()]
    S =     _in[0]   # type:str
    # vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
    len_S = len(S)
    cnt = 0
    for i in range(len_S):
        for j in range(i+3,len_S):
            if j == i+3:
                mod = int(S[len_S-j-1:len_S-i])%3
            else:
                mod = (mod+int(S[len_S-j-1]))%3
            if mod == 0:
                _ = int(S[len_S-j-1:len_S-i])
                if _%673==0:
                    cnt += 1
                    break
    # ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    print(cnt)


if __name__ == "__main__":
    #main()

    _in = [_.rstrip() for _ in stdin.readlines()]
    S =     _in[0]   # type:str
    # vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
    cnt = 0
    mod_arr = [0] * 2019
    mod_arr[0] += 1

    num, dec = 0, 1
    for s in S[::-1]:
        num += int(s)*dec
        num %= 2019
        dec *= 10
        dec %= 2019
        mod_arr[num] += 1

    for i in range(2019):
        if mod_arr[i] > 0:
            cnt += mod_arr[i]*(mod_arr[i]-1)//2
    # ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    print(cnt)

Buggy python submission (verdict: Time Limit Exceeded):
from sys import stdin
from collections import Counter


def main():
    _in = [_.rstrip() for _ in stdin.readlines()]
    S =     _in[0]   # type:str
    # vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
    len_S = len(S)
    cnt = 0
    for i in range(len_S):
        for j in range(i+3,len_S):
            if j == i+3:
                mod = int(S[len_S-j-1:len_S-i])%3
            else:
                mod = (mod+int(S[len_S-j-1]))%3
            if mod == 0:
                _ = int(S[len_S-j-1:len_S-i])
                if _%673==0:
                    cnt += 1
                    break
    # ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    print(cnt)


def ans():
    _in = [_.rstrip() for _ in stdin.readlines()]
    S =     _in[0]   # type:str
    # vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
    len_S = len(S)
    cnt = 0
    mod_arr = [0]
    for i in range(0,len_S+1):
        _ = int(S[len_S-i-1:])
        if i==0: mod = _%2019
        else: mod = (mod+int(S[len_S-i-1])*10**i)%2019
        mod_arr.append(mod)
    mod_count = Counter(mod_arr)
    for value in mod_count.values():
        if value>1:
            cnt += value*(value-1)//2
    # ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    print(cnt)


if __name__ == "__main__":
    #main()
    ans()


Fixed submission:
from sys import stdin


def main():
    _in = [_.rstrip() for _ in stdin.readlines()]
    S =     _in[0]   # type:str
    # vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
    len_S = len(S)
    cnt = 0
    for i in range(len_S):
        for j in range(i+3,len_S):
            if j == i+3:
                mod = int(S[len_S-j-1:len_S-i])%3
            else:
                mod = (mod+int(S[len_S-j-1]))%3
            if mod == 0:
                _ = int(S[len_S-j-1:len_S-i])
                if _%673==0:
                    cnt += 1
                    break
    # ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    print(cnt)


if __name__ == "__main__":
    #main()

    _in = [_.rstrip() for _ in stdin.readlines()]
    S =     _in[0]   # type:str
    # vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
    cnt = 0
    mod_arr = [0] * 2019
    mod_arr[0] += 1

    num, dec = 0, 1
    for s in S[::-1]:
        num += int(s)*dec
        num %= 2019
        dec *= 10
        dec %= 2019
        mod_arr[num] += 1

    for i in range(2019):
        if mod_arr[i] > 0:
            cnt += mod_arr[i]*(mod_arr[i]-1)//2
    # ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    print(cnt)

Buggy python submission (verdict: Time Limit Exceeded):
from sys import stdin
from collections import Counter


def main():
    _in = [_.rstrip() for _ in stdin.readlines()]
    S =     _in[0]   # type:str
    # vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
    len_S = len(S)
    cnt = 0
    for i in range(len_S):
        for j in range(i+3,len_S):
            if j == i+3:
                mod = int(S[len_S-j-1:len_S-i])%3
            else:
                mod = (mod+int(S[len_S-j-1]))%3
            if mod == 0:
                _ = int(S[len_S-j-1:len_S-i])
                if _%673==0:
                    cnt += 1
                    break
    # ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    print(cnt)


def ans():
    _in = [_.rstrip() for _ in stdin.readlines()]
    S =     _in[0]   # type:str
    # vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
    len_S = len(S)
    cnt = 0
    mod_arr = []
    for i in range(0,len_S+1):
        if len(S[len_S-i:])==0: 
            mod_arr.append(0)
        else:
            _ = int(S[len_S-i:])
            if i==1: mod = _%2019
            else: mod = (mod+int(S[len_S-i])*10**(i-1))%2019
            mod_arr.append(mod)
    mod_count = Counter(mod_arr)
    for value in mod_count.values():
        if value>1:
            cnt += value*(value-1)//2
    # ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    print(cnt)


if __name__ == "__main__":
    #main()
    ans()


Fixed submission:
from sys import stdin


def main():
    _in = [_.rstrip() for _ in stdin.readlines()]
    S =     _in[0]   # type:str
    # vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
    len_S = len(S)
    cnt = 0
    for i in range(len_S):
        for j in range(i+3,len_S):
            if j == i+3:
                mod = int(S[len_S-j-1:len_S-i])%3
            else:
                mod = (mod+int(S[len_S-j-1]))%3
            if mod == 0:
                _ = int(S[len_S-j-1:len_S-i])
                if _%673==0:
                    cnt += 1
                    break
    # ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    print(cnt)


if __name__ == "__main__":
    #main()

    _in = [_.rstrip() for _ in stdin.readlines()]
    S =     _in[0]   # type:str
    # vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
    cnt = 0
    mod_arr = [0] * 2019
    mod_arr[0] += 1

    num, dec = 0, 1
    for s in S[::-1]:
        num += int(s)*dec
        num %= 2019
        dec *= 10
        dec %= 2019
        mod_arr[num] += 1

    for i in range(2019):
        if mod_arr[i] > 0:
            cnt += mod_arr[i]*(mod_arr[i]-1)//2
    # ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    print(cnt)

Buggy python submission (verdict: Time Limit Exceeded):
from sys import stdin


if __name__ == "__main__":
    _in = [_.rstrip() for _ in stdin.readlines()]
    S =     _in[0]   # type:str
    # vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
    len_S = len(S)
    cnt = 0
    for i in range(len_S):
        for j in range(i+3,len_S):
            if j == i+3:
                mod = int(S[len_S-j-1:len_S-i])%3
            else:
                mod = (mod+int(S[len_S-j-1]))%3
            if mod == 0:
                _ = int(S[len_S-j-1:len_S-i])
                if _%673==0:
                    cnt += 1
                    break
    # ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    print(cnt)


Fixed submission:
from sys import stdin


def main():
    _in = [_.rstrip() for _ in stdin.readlines()]
    S =     _in[0]   # type:str
    # vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
    len_S = len(S)
    cnt = 0
    for i in range(len_S):
        for j in range(i+3,len_S):
            if j == i+3:
                mod = int(S[len_S-j-1:len_S-i])%3
            else:
                mod = (mod+int(S[len_S-j-1]))%3
            if mod == 0:
                _ = int(S[len_S-j-1:len_S-i])
                if _%673==0:
                    cnt += 1
                    break
    # ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    print(cnt)


if __name__ == "__main__":
    #main()

    _in = [_.rstrip() for _ in stdin.readlines()]
    S =     _in[0]   # type:str
    # vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
    cnt = 0
    mod_arr = [0] * 2019
    mod_arr[0] += 1

    num, dec = 0, 1
    for s in S[::-1]:
        num += int(s)*dec
        num %= 2019
        dec *= 10
        dec %= 2019
        mod_arr[num] += 1

    for i in range(2019):
        if mod_arr[i] > 0:
            cnt += mod_arr[i]*(mod_arr[i]-1)//2
    # ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    print(cnt)

Buggy python submission (verdict: Time Limit Exceeded):
from sys import stdin


if __name__ == "__main__":
    _in = [_.rstrip() for _ in stdin.readlines()]
    S =     _in[0]   # type:str
    # vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
    len_S = len(S)
    cnt = 0
    for i in range(len_S):
        for j in range(i+3,len_S):
            if j == i+3:
                mod = int(S[len_S-j-1:len_S-i])%3
            else:
                mod = (mod+int(S[len_S-j-1]))%3
            if mod == 0:
                _ = int(S[len_S-j-1:len_S-i])
                if _%673==0:
                    cnt += 1
    # ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    print(cnt)


Fixed submission:
from sys import stdin


def main():
    _in = [_.rstrip() for _ in stdin.readlines()]
    S =     _in[0]   # type:str
    # vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
    len_S = len(S)
    cnt = 0
    for i in range(len_S):
        for j in range(i+3,len_S):
            if j == i+3:
                mod = int(S[len_S-j-1:len_S-i])%3
            else:
                mod = (mod+int(S[len_S-j-1]))%3
            if mod == 0:
                _ = int(S[len_S-j-1:len_S-i])
                if _%673==0:
                    cnt += 1
                    break
    # ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    print(cnt)


if __name__ == "__main__":
    #main()

    _in = [_.rstrip() for _ in stdin.readlines()]
    S =     _in[0]   # type:str
    # vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
    cnt = 0
    mod_arr = [0] * 2019
    mod_arr[0] += 1

    num, dec = 0, 1
    for s in S[::-1]:
        num += int(s)*dec
        num %= 2019
        dec *= 10
        dec %= 2019
        mod_arr[num] += 1

    for i in range(2019):
        if mod_arr[i] > 0:
            cnt += mod_arr[i]*(mod_arr[i]-1)//2
    # ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    print(cnt)

Buggy python submission (verdict: Time Limit Exceeded):
from sys import stdin


if __name__ == "__main__":
    _in = [_.rstrip() for _ in stdin.readlines()]
    S =     _in[0]   # type:str
    # vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
    len_S = len(S)
    memo = set()
    cnt = 0
    for i in range(len_S):
        for j in range(i+3,len_S):
            if j == i+3:
                mod = int(S[len_S-j-1:len_S-i])%3
            else:
                mod = (mod+int(S[len_S-j-1]))%3
            if mod == 0:
                _ = int(S[len_S-j-1:len_S-i])
                if _ in memo:
                    cnt += 1
                elif _%673==0:
                    cnt += 1
                    memo.add(_)
    # ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    print(cnt)


Fixed submission:
from sys import stdin


def main():
    _in = [_.rstrip() for _ in stdin.readlines()]
    S =     _in[0]   # type:str
    # vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
    len_S = len(S)
    cnt = 0
    for i in range(len_S):
        for j in range(i+3,len_S):
            if j == i+3:
                mod = int(S[len_S-j-1:len_S-i])%3
            else:
                mod = (mod+int(S[len_S-j-1]))%3
            if mod == 0:
                _ = int(S[len_S-j-1:len_S-i])
                if _%673==0:
                    cnt += 1
                    break
    # ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    print(cnt)


if __name__ == "__main__":
    #main()

    _in = [_.rstrip() for _ in stdin.readlines()]
    S =     _in[0]   # type:str
    # vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
    cnt = 0
    mod_arr = [0] * 2019
    mod_arr[0] += 1

    num, dec = 0, 1
    for s in S[::-1]:
        num += int(s)*dec
        num %= 2019
        dec *= 10
        dec %= 2019
        mod_arr[num] += 1

    for i in range(2019):
        if mod_arr[i] > 0:
            cnt += mod_arr[i]*(mod_arr[i]-1)//2
    # ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    print(cnt)

Buggy python submission (verdict: Time Limit Exceeded):
from sys import stdin


if __name__ == "__main__":
    _in = [_.rstrip() for _ in stdin.readlines()]
    S =     _in[0]   # type:str
    # vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
    len_S = len(S)
    memo = set()
    cnt = 0
    for i in range(len_S):
        for j in range(i+3,len_S):
            #print(int(S[len_S-j-1:len_S-i]))
            if j == i+3:
                mod = int(S[len_S-j-1:len_S-i])%3
            else:
                mod = (mod+int(S[len_S-j-1]))%3
            if mod == 0:
                _ = int(S[len_S-j-1:len_S-i])
                if _ in memo:
                    cnt += 1
                elif _%2019==0:
                    cnt += 1
                    memo.add(_)
    # ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    print(cnt)


Fixed submission:
from sys import stdin


def main():
    _in = [_.rstrip() for _ in stdin.readlines()]
    S =     _in[0]   # type:str
    # vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
    len_S = len(S)
    cnt = 0
    for i in range(len_S):
        for j in range(i+3,len_S):
            if j == i+3:
                mod = int(S[len_S-j-1:len_S-i])%3
            else:
                mod = (mod+int(S[len_S-j-1]))%3
            if mod == 0:
                _ = int(S[len_S-j-1:len_S-i])
                if _%673==0:
                    cnt += 1
                    break
    # ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    print(cnt)


if __name__ == "__main__":
    #main()

    _in = [_.rstrip() for _ in stdin.readlines()]
    S =     _in[0]   # type:str
    # vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
    cnt = 0
    mod_arr = [0] * 2019
    mod_arr[0] += 1

    num, dec = 0, 1
    for s in S[::-1]:
        num += int(s)*dec
        num %= 2019
        dec *= 10
        dec %= 2019
        mod_arr[num] += 1

    for i in range(2019):
        if mod_arr[i] > 0:
            cnt += mod_arr[i]*(mod_arr[i]-1)//2
    # ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    print(cnt)

Buggy python submission (verdict: Time Limit Exceeded):
from sys import stdin

if __name__ == "__main__":
    _in = [_.rstrip() for _ in stdin.readlines()]
    S =     _in[0]   # type:str
    # vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
    memo = set()
    cnt = 0
    for i in range(len(S)):
        for j in range(i+3,len(S)):
            if j == i+3:
                mod = int(S[len(S)-j-1:len(S)-i])%3
            else:
                mod = (mod+int(S[len(S)-j-1]))%3
            if mod == 0:
                _ = int(S[len(S)-j-1:len(S)-i])
                if _ in memo:
                    cnt += 1
                elif _%2019==0:
                    cnt += 1
                    memo.add(_)
    # ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    print(cnt)


Fixed submission:
from sys import stdin


def main():
    _in = [_.rstrip() for _ in stdin.readlines()]
    S =     _in[0]   # type:str
    # vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
    len_S = len(S)
    cnt = 0
    for i in range(len_S):
        for j in range(i+3,len_S):
            if j == i+3:
                mod = int(S[len_S-j-1:len_S-i])%3
            else:
                mod = (mod+int(S[len_S-j-1]))%3
            if mod == 0:
                _ = int(S[len_S-j-1:len_S-i])
                if _%673==0:
                    cnt += 1
                    break
    # ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    print(cnt)


if __name__ == "__main__":
    #main()

    _in = [_.rstrip() for _ in stdin.readlines()]
    S =     _in[0]   # type:str
    # vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
    cnt = 0
    mod_arr = [0] * 2019
    mod_arr[0] += 1

    num, dec = 0, 1
    for s in S[::-1]:
        num += int(s)*dec
        num %= 2019
        dec *= 10
        dec %= 2019
        mod_arr[num] += 1

    for i in range(2019):
        if mod_arr[i] > 0:
            cnt += mod_arr[i]*(mod_arr[i]-1)//2
    # ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    print(cnt)

Buggy python submission (verdict: Time Limit Exceeded):
from sys import stdin

if __name__ == "__main__":
    _in = [_.rstrip() for _ in stdin.readlines()]
    S =     _in[0]   # type:str
    # vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
    memo = set()
    cnt = 0
    for i in range(len(S)):
        for j in range(i+3,len(S)):
            if j == i+3:
                mod = int(S[len(S)-j-1:len(S)-i])%3
            else:
                mod = (mod+int(S[len(S)-j-1]))%3
            if mod == 0:
                _ = int(S[len(S)-j-1:len(S)-i])
                if _ in memo:
                    cnt += 1
                elif _%2019==0:
                    cnt += 1
                    memo.add(_)
    # ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    print(cnt)


Fixed submission:
from sys import stdin


def main():
    _in = [_.rstrip() for _ in stdin.readlines()]
    S =     _in[0]   # type:str
    # vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
    len_S = len(S)
    cnt = 0
    for i in range(len_S):
        for j in range(i+3,len_S):
            if j == i+3:
                mod = int(S[len_S-j-1:len_S-i])%3
            else:
                mod = (mod+int(S[len_S-j-1]))%3
            if mod == 0:
                _ = int(S[len_S-j-1:len_S-i])
                if _%673==0:
                    cnt += 1
                    break
    # ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    print(cnt)


if __name__ == "__main__":
    #main()

    _in = [_.rstrip() for _ in stdin.readlines()]
    S =     _in[0]   # type:str
    # vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
    cnt = 0
    mod_arr = [0] * 2019
    mod_arr[0] += 1

    num, dec = 0, 1
    for s in S[::-1]:
        num += int(s)*dec
        num %= 2019
        dec *= 10
        dec %= 2019
        mod_arr[num] += 1

    for i in range(2019):
        if mod_arr[i] > 0:
            cnt += mod_arr[i]*(mod_arr[i]-1)//2
    # ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    print(cnt)

Buggy python submission (verdict: Time Limit Exceeded):
from sys import stdin

if __name__ == "__main__":
    _in = [_.rstrip() for _ in stdin.readlines()]
    S =     _in[0]   # type:str
    # vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
    memo = set()
    cnt = 0
    for i in range(len(S)):
        for j in range(i+3,len(S)):
            if j == i+3:
                mod = int(S[len(S)-j-1:len(S)-i])%3
            else:
                mod = (mod+int(S[len(S)-j-1]))%3
            if mod == 0:
                _ = int(S[len(S)-j-1:len(S)-i])
                if _%2019==0:
                    cnt += 1
    # ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    print(cnt)


Fixed submission:
from sys import stdin


def main():
    _in = [_.rstrip() for _ in stdin.readlines()]
    S =     _in[0]   # type:str
    # vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
    len_S = len(S)
    cnt = 0
    for i in range(len_S):
        for j in range(i+3,len_S):
            if j == i+3:
                mod = int(S[len_S-j-1:len_S-i])%3
            else:
                mod = (mod+int(S[len_S-j-1]))%3
            if mod == 0:
                _ = int(S[len_S-j-1:len_S-i])
                if _%673==0:
                    cnt += 1
                    break
    # ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    print(cnt)


if __name__ == "__main__":
    #main()

    _in = [_.rstrip() for _ in stdin.readlines()]
    S =     _in[0]   # type:str
    # vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
    cnt = 0
    mod_arr = [0] * 2019
    mod_arr[0] += 1

    num, dec = 0, 1
    for s in S[::-1]:
        num += int(s)*dec
        num %= 2019
        dec *= 10
        dec %= 2019
        mod_arr[num] += 1

    for i in range(2019):
        if mod_arr[i] > 0:
            cnt += mod_arr[i]*(mod_arr[i]-1)//2
    # ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    print(cnt)

Buggy python submission (verdict: Time Limit Exceeded):
from sys import stdin


if __name__ == "__main__":
    _in = [_.rstrip() for _ in stdin.readlines()]
    S =     _in[0]   # type:str
    # vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
    memo = set()
    cnt = 0
    for i in range(len(S)):
        for j in range(i+3,len(S)):
            _ = int(S[i:j+1])
            if _ in memo:
                cnt += 1
            elif _%2019==0:
                cnt += 1
                memo.add(_)
    # ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    print(cnt)


Fixed submission:
from sys import stdin


def main():
    _in = [_.rstrip() for _ in stdin.readlines()]
    S =     _in[0]   # type:str
    # vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
    len_S = len(S)
    cnt = 0
    for i in range(len_S):
        for j in range(i+3,len_S):
            if j == i+3:
                mod = int(S[len_S-j-1:len_S-i])%3
            else:
                mod = (mod+int(S[len_S-j-1]))%3
            if mod == 0:
                _ = int(S[len_S-j-1:len_S-i])
                if _%673==0:
                    cnt += 1
                    break
    # ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    print(cnt)


if __name__ == "__main__":
    #main()

    _in = [_.rstrip() for _ in stdin.readlines()]
    S =     _in[0]   # type:str
    # vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
    cnt = 0
    mod_arr = [0] * 2019
    mod_arr[0] += 1

    num, dec = 0, 1
    for s in S[::-1]:
        num += int(s)*dec
        num %= 2019
        dec *= 10
        dec %= 2019
        mod_arr[num] += 1

    for i in range(2019):
        if mod_arr[i] > 0:
            cnt += mod_arr[i]*(mod_arr[i]-1)//2
    # ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    print(cnt)