Buggy python submission (verdict: Runtime Error):
import sys
import numpy as np

def solve(S):
	M = 2019
	t = 1
	ans = 0
	c = np.zeros(M, dtype=np.int64)
	c[0] = 1
	r = 0
	for d in S:
		r = (d * t + r) % M
		ans += c[r]
		c[r] += 1
		t = t * 10 % M
	return ans



def cc_export():
	from numba.pycc import CC
	cc = CC('my_module')
    S = np.array([], dtype=np.int32)
	cc.export('solve', numba.i8(numba.typeof(S)))(solve)
	cc.compile()

if __name__ == '__main__':
	import sys
	if sys.argv[-1] == 'ONLINE_JUDGE':
		cc_export()
		exit(0)
	from my_module import solve
	S = sys.stdin.buffer.readline().decode('utf-8').rstrip()
	S = np.array([int(d) for d in S[::-1]], dtype=np.int32)
	print(solve(S))


Fixed submission:
import sys

M = 2019
S = sys.stdin.readline().rstrip()
N = len(S)

dmod = [0] * (N + 1)
amod = [0] * (N + 1)
tenmod = 1
prev_amod = 0
mcnt = [0] * 2019
ans = 0
for i in range(N, -1, -1):
    d = ord(S[i]) - ord("0") if i < N else 0
    dmod[i] = d * tenmod % M
    amod[i] = (dmod[i] + prev_amod) % M
    ans += mcnt[amod[i]]
    mcnt[amod[i]] += 1
    tenmod = tenmod * 10 % M
    prev_amod = amod[i]
print(ans)

Buggy python submission (verdict: Runtime Error):
import sys
import numpy as np
S = sys.stdin.buffer.readline().decode('utf-8').rstrip()
S = np.array([int(d) for d in S[::-1]], dtype=np.int32)

def solve(S):
	M = 2019
	t = 1
	ans = 0
	c = np.zeros(M, dtype=np.int64)
	c[0] = 1
	r = 0
	for d in S:
		r = (d * t + r) % M
		ans += c[r]
		c[r] += 1
		t = t * 10 % M
	return ans



def cc_export():
	from numba.pycc import CC
	cc = CC('my_module')
	cc.export('solve', numba.i8(numba.typeof(S)))(solve)
	cc.compile()

if __name__ == '__main__':
	import sys
	if sys.argv[-1] == 'ONLINE_JUDGE':
		cc_export()
		exit(0)
	from my_module import solve
	print(solve(S))


Fixed submission:
import sys

M = 2019
S = sys.stdin.readline().rstrip()
N = len(S)

dmod = [0] * (N + 1)
amod = [0] * (N + 1)
tenmod = 1
prev_amod = 0
mcnt = [0] * 2019
ans = 0
for i in range(N, -1, -1):
    d = ord(S[i]) - ord("0") if i < N else 0
    dmod[i] = d * tenmod % M
    amod[i] = (dmod[i] + prev_amod) % M
    ans += mcnt[amod[i]]
    mcnt[amod[i]] += 1
    tenmod = tenmod * 10 % M
    prev_amod = amod[i]
print(ans)

Buggy python submission (verdict: Time Limit Exceeded):
s=input();n=len(s);t=1;p=0;c=[0]*2019;r=0
for i in range(n+1):p=((ord(s[n-i])-ord("0")if i>0 else 0)*t+p)%2019;r+=c[p];c[p]+=1;t*=10
print(r)

Fixed submission:
import sys

M = 2019
S = sys.stdin.readline().rstrip()
N = len(S)

dmod = [0] * (N + 1)
amod = [0] * (N + 1)
tenmod = 1
prev_amod = 0
mcnt = [0] * 2019
ans = 0
for i in range(N, -1, -1):
    d = ord(S[i]) - ord("0") if i < N else 0
    dmod[i] = d * tenmod % M
    amod[i] = (dmod[i] + prev_amod) % M
    ans += mcnt[amod[i]]
    mcnt[amod[i]] += 1
    tenmod = tenmod * 10 % M
    prev_amod = amod[i]
print(ans)

Buggy python submission (verdict: Time Limit Exceeded):
s=input();n=len(s);t=1;p=0;c=[0]*2019;r=0
for i in range(n+1):p=((ord(s[n-i])-ord("0")if i>0 else 0)*t+p)%2019;r+=c[p];c[p]+=1;t*=10
print(r)

Fixed submission:
import sys

M = 2019
S = sys.stdin.readline().rstrip()
N = len(S)

dmod = [0] * (N + 1)
amod = [0] * (N + 1)
tenmod = 1
prev_amod = 0
mcnt = [0] * 2019
ans = 0
for i in range(N, -1, -1):
    d = ord(S[i]) - ord("0") if i < N else 0
    dmod[i] = d * tenmod % M
    amod[i] = (dmod[i] + prev_amod) % M
    ans += mcnt[amod[i]]
    mcnt[amod[i]] += 1
    tenmod = tenmod * 10 % M
    prev_amod = amod[i]
print(ans)