Buggy python submission (verdict: Time Limit Exceeded):
#input
S = str(input())[::-1]

#output
from collections import Counter
#2019 = 3 * 673
N = len(S)
#上からi桁目までの数を決めた時2019の個数をdp[i]とする。
dp = [0] * (N)
dp[0] = int(S[0])
for i in range(N-1):
    dp[i+1] = (dp[i] + int(S[i+1]) * 10**(i+1)) % 2019

T = Counter(dp)

answer = T[0]

for t in T.values():
    answer += t*(t-1)//2

print(answer)

Fixed submission:
#input
S = str(input())[::-1]

#output
from collections import Counter
#2019 = 3 * 673
N = len(S)
#上からi桁目までの数を決めた時2019の個数をdp[i]とする。
dp = [0] * (N)
dp[0] = int(S[0])
times =10
for i in range(N-1):
    dp[i+1] = dp[i] + times * int(S[i+1])
    dp[i+1] %= 2019
    times *= 10
    times %= 2019

T = Counter(dp)

answer = T[0]

for t in T.values():
    answer += t*(t-1)//2

print(answer)

Buggy python submission (verdict: Time Limit Exceeded):
#input
S = str(input())[::-1]

#output
from collections import Counter
#2019 = 3 * 673
N = len(S)
#上からi桁目までの数を決めた時2019の個数をdp[i]とする。
dp = [0] * (N)
dp[0] = int(S[0])
for i in range(N-1):
    dp[i+1] = (dp[i] + int(S[i+1]) * 10**(i+1)) % 2019

T = Counter(dp)

answer = T[0]

for t in T.values():
    answer += t*(t-1)//2

print(answer)

Fixed submission:
#input
S = str(input())[::-1]

#output
from collections import Counter
#2019 = 3 * 673
N = len(S)
#上からi桁目までの数を決めた時2019の個数をdp[i]とする。
dp = [0] * (N)
dp[0] = int(S[0])
times =10
for i in range(N-1):
    dp[i+1] = dp[i] + times * int(S[i+1])
    dp[i+1] %= 2019
    times *= 10
    times %= 2019

T = Counter(dp)

answer = T[0]

for t in T.values():
    answer += t*(t-1)//2

print(answer)

Buggy python submission (verdict: Time Limit Exceeded):
#input
S = str(input())

#output
from collections import Counter
#2019 = 3 * 673
N = len(S)
#上からi桁目までの数を決めた時2019の個数をdp[i]とする。
dp = [0] * (N+1)
dp[1] = int(S[-1])
for i in range(1, N):
    dp[i+1] = (dp[i] + int(S[-(i+1)]) * 10**i) % 2019

T = Counter(dp[1:])

answer = 0
answer += T[0]

for t in T.values():
    answer += t*(t-1)//2

print(answer)

Fixed submission:
#input
S = str(input())[::-1]

#output
from collections import Counter
#2019 = 3 * 673
N = len(S)
#上からi桁目までの数を決めた時2019の個数をdp[i]とする。
dp = [0] * (N)
dp[0] = int(S[0])
times =10
for i in range(N-1):
    dp[i+1] = dp[i] + times * int(S[i+1])
    dp[i+1] %= 2019
    times *= 10
    times %= 2019

T = Counter(dp)

answer = T[0]

for t in T.values():
    answer += t*(t-1)//2

print(answer)

Buggy python submission (verdict: Time Limit Exceeded):
#input
S = str(input())

#output
from collections import Counter
#2019 = 3 * 673
N = len(S)
#上からi桁目までの数を決めた時2019の個数をdp[i]とする。
dp = [0] * (N+1)
dp[1] = int(S[-1])
for i in range(1, N):
    dp[i+1] = (dp[i] + int(S[-(i+1)]) * 10**i) % 2019

T = Counter(dp[1:])

answer = 0
answer += T[0]

for t in T.values():
    if t >= 2:
        answer += t*(t-1)//2

print(answer)

Fixed submission:
#input
S = str(input())[::-1]

#output
from collections import Counter
#2019 = 3 * 673
N = len(S)
#上からi桁目までの数を決めた時2019の個数をdp[i]とする。
dp = [0] * (N)
dp[0] = int(S[0])
times =10
for i in range(N-1):
    dp[i+1] = dp[i] + times * int(S[i+1])
    dp[i+1] %= 2019
    times *= 10
    times %= 2019

T = Counter(dp)

answer = T[0]

for t in T.values():
    answer += t*(t-1)//2

print(answer)

Buggy python submission (verdict: Time Limit Exceeded):
#input
S = str(input())

#output
from collections import Counter
#2019 = 3 * 673
N = len(S)
#上からi桁目までの数を決めた時2019の個数をdp[i]とする。
dp = [0] * (N+1)

for i in range(1, N+1):
    dp[i] = int(S[-i::]) % 2019

T = Counter(dp[1:])

answer = 0
answer += T[0]

for t in T.values():
    if t >= 2:
        answer += t*(t-1)//2

print(answer)

Fixed submission:
#input
S = str(input())[::-1]

#output
from collections import Counter
#2019 = 3 * 673
N = len(S)
#上からi桁目までの数を決めた時2019の個数をdp[i]とする。
dp = [0] * (N)
dp[0] = int(S[0])
times =10
for i in range(N-1):
    dp[i+1] = dp[i] + times * int(S[i+1])
    dp[i+1] %= 2019
    times *= 10
    times %= 2019

T = Counter(dp)

answer = T[0]

for t in T.values():
    answer += t*(t-1)//2

print(answer)

Buggy python submission (verdict: Time Limit Exceeded):
#input
S = str(input())

#output
import numpy as np
from collections import Counter
#2019 = 3 * 673
N = len(S)
#上からi桁目までの数を決めた時2019の個数をdp[i]とする。
dp = np.zeros(N+1, int)

for i in range(1, N+1):
    dp[i] = int(S[-i::]) % 2019

T = Counter(dp[1:])

answer = 0
answer += T[0]

for t in T.values():
    if t >= 2:
        answer += t*(t-1)//2

print(answer)

Fixed submission:
#input
S = str(input())[::-1]

#output
from collections import Counter
#2019 = 3 * 673
N = len(S)
#上からi桁目までの数を決めた時2019の個数をdp[i]とする。
dp = [0] * (N)
dp[0] = int(S[0])
times =10
for i in range(N-1):
    dp[i+1] = dp[i] + times * int(S[i+1])
    dp[i+1] %= 2019
    times *= 10
    times %= 2019

T = Counter(dp)

answer = T[0]

for t in T.values():
    answer += t*(t-1)//2

print(answer)