Buggy python submission (verdict: Runtime Error):
# -*- coding: utf-8 -*-
"""
Created on Sat Sep 19 22:03:19 2020

@author: liang
"""

N, X, M = map(int,input().split())
mod_set = {X}
mod_lis = [X]
A = [0]*(10**6+1)
A[0] = X
flag = False
#for i in range(1,N):
for i in range(1,min(10**6,N)):
    tmp = A[i-1]**2%M
    if tmp in mod_set:
        flag = True
        break
    A[i] = tmp
    mod_set.add(tmp)
    mod_lis.append(tmp)

if flag:
    j = mod_lis.index(tmp)
else:
    j = i
T = i - j
ans = 0
if T != 0:  
    ans += sum(mod_lis[:j])
    T_sum = sum(mod_lis[j:])
    """
    【切り捨て演算は必ず()をつけて先に計算】
    """
    ans += T_sum * ((N-j)//T)
    #print((N-j)//T, T_sum)
    T_lis = mod_lis[j:i]   
    ans += sum(T_lis[:(N-j)%T])
else:
    ans = sum(mod_lis)
#print(T_lis)
#print((N-j)%T)
#print(T_lis[:10])
print(ans)
#print(T_sum)
#print(sum(T_lis))

Fixed submission:
# -*- coding: utf-8 -*-
"""
Created on Sat Sep 19 22:58:03 2020

@author: liang
"""

N,X,M=map(int,input().split())
a = X
hist = [a]
indices = [-1]*M
indices[a] = 0
flag=0
for i in range(1,min(10**6,N)):
  a = a**2 % M
  if indices[a] != -1:
    idx = indices[a]
    flag=1
    break
  hist.append(a)
  indices[a] = i
  
if flag==0:
  print(sum(hist))
  exit()
  
cycle = hist[idx:]
margin = hist[:idx]
q,r = divmod((N-len(margin)),len(cycle))
ans = 0
ans += sum(margin)
ans += sum(cycle)*q
#print(q,sum(cycle))
ans += sum(cycle[:r])
#print(r)
#print(cycle[:10])
print(ans)

Buggy python submission (verdict: Runtime Error):
# -*- coding: utf-8 -*-
"""
Created on Sat Sep 19 22:03:19 2020

@author: liang
"""

N, X, M = map(int,input().split())
mod_set = {X}
mod_lis = [X]
A = [0]*(10**6+1)
A[0] = X
flag = False
#for i in range(1,N):
for i in range(1,min(10**6,N)):
    tmp = A[i-1]**2%M
    if tmp in mod_set:
        flag = True
        break
    A[i] = tmp
    mod_set.add(tmp)
    mod_lis.append(tmp)

if flag:
    j = mod_lis.index(tmp)
else:
    j = i
T = i - j
ans = 0
if T != -1:  
    ans += sum(mod_lis[:j])
    T_sum = sum(mod_lis[j:])
    """
    【切り捨て演算は必ず()をつけて先に計算】
    """
    ans += T_sum * ((N-j)//T)
    #print((N-j)//T, T_sum)
    T_lis = mod_lis[j:i]   
    ans += sum(T_lis[:(N-j)%T])
else:
    ans = sum(mod_lis)
#print(T_lis)
#print((N-j)%T)
#print(T_lis[:10])
print(ans)
#print(T_sum)
#print(sum(T_lis))

Fixed submission:
# -*- coding: utf-8 -*-
"""
Created on Sat Sep 19 22:58:03 2020

@author: liang
"""

N,X,M=map(int,input().split())
a = X
hist = [a]
indices = [-1]*M
indices[a] = 0
flag=0
for i in range(1,min(10**6,N)):
  a = a**2 % M
  if indices[a] != -1:
    idx = indices[a]
    flag=1
    break
  hist.append(a)
  indices[a] = i
  
if flag==0:
  print(sum(hist))
  exit()
  
cycle = hist[idx:]
margin = hist[:idx]
q,r = divmod((N-len(margin)),len(cycle))
ans = 0
ans += sum(margin)
ans += sum(cycle)*q
#print(q,sum(cycle))
ans += sum(cycle[:r])
#print(r)
#print(cycle[:10])
print(ans)

Buggy python submission (verdict: Runtime Error):
# -*- coding: utf-8 -*-
"""
Created on Sat Sep 19 22:03:19 2020

@author: liang
"""

N, X, M = map(int,input().split())
mod_set = {X}
mod_lis = [X]
A = [0]*(10**6+1)
A[0] = X
#for i in range(1,N):
for i in range(1,min(10**6,N)):
    tmp = A[i-1]**2%M
    if tmp in mod_set:
        break
    A[i] = tmp
    mod_set.add(tmp)
    mod_lis.append(tmp)

j = mod_lis.index(tmp)
T = i - j
ans = 0
if T != 0:  
    ans += sum(mod_lis[:j])
    T_sum = sum(mod_lis[j:])
    """
    【切り捨て演算は必ず()をつけて先に計算】
    """
    ans += T_sum * ((N-j)//T)
    #print((N-j)//T, T_sum)
    T_lis = mod_lis[j:i]   
    ans += sum(T_lis[:(N-j)%T])
else:
    ans = sum(mod_lis)
#print(T_lis)
#print((N-j)%T)
#print(T_lis[:10])
print(ans)
#print(T_sum)
#print(sum(T_lis))


Fixed submission:
# -*- coding: utf-8 -*-
"""
Created on Sat Sep 19 22:58:03 2020

@author: liang
"""

N,X,M=map(int,input().split())
a = X
hist = [a]
indices = [-1]*M
indices[a] = 0
flag=0
for i in range(1,min(10**6,N)):
  a = a**2 % M
  if indices[a] != -1:
    idx = indices[a]
    flag=1
    break
  hist.append(a)
  indices[a] = i
  
if flag==0:
  print(sum(hist))
  exit()
  
cycle = hist[idx:]
margin = hist[:idx]
q,r = divmod((N-len(margin)),len(cycle))
ans = 0
ans += sum(margin)
ans += sum(cycle)*q
#print(q,sum(cycle))
ans += sum(cycle[:r])
#print(r)
#print(cycle[:10])
print(ans)

Buggy python submission (verdict: Runtime Error):
# -*- coding: utf-8 -*-
"""
Created on Sat Sep 19 22:03:19 2020

@author: liang
"""

N, X, M = map(int,input().split())
mod_set = {X}
mod_lis = [X]
A = [0]*(10**5+1)
A[0] = X
for i in range(1,N):
    tmp = A[i-1]**2%M
    if tmp in mod_set:
        break
    A[i] = tmp
    mod_set.add(tmp)
    mod_lis.append(tmp)

j = mod_lis.index(tmp)
T = i - j
ans = 0
if T != 0:  
    ans += sum(mod_lis[:j])
    T_sum = sum(mod_lis[j:])
    """
    【切り捨て演算は必ず()をつけて先に計算】
    """
    ans += T_sum * ((N-j)//T)
    #print((N-j)//T, T_sum)
    T_lis = mod_lis[j:i]   
    ans += sum(T_lis[:(N-j)%T])
else:
    ans = sum(mod_lis)
#print(T_lis)
#print((N-j)%T)
#print(T_lis[:10])
print(ans)
#print(T_sum)
#print(sum(T_lis))

Fixed submission:
# -*- coding: utf-8 -*-
"""
Created on Sat Sep 19 22:58:03 2020

@author: liang
"""

N,X,M=map(int,input().split())
a = X
hist = [a]
indices = [-1]*M
indices[a] = 0
flag=0
for i in range(1,min(10**6,N)):
  a = a**2 % M
  if indices[a] != -1:
    idx = indices[a]
    flag=1
    break
  hist.append(a)
  indices[a] = i
  
if flag==0:
  print(sum(hist))
  exit()
  
cycle = hist[idx:]
margin = hist[:idx]
q,r = divmod((N-len(margin)),len(cycle))
ans = 0
ans += sum(margin)
ans += sum(cycle)*q
#print(q,sum(cycle))
ans += sum(cycle[:r])
#print(r)
#print(cycle[:10])
print(ans)

Buggy python submission (verdict: Runtime Error):
# -*- coding: utf-8 -*-
"""
Created on Sat Sep 19 22:03:19 2020

@author: liang
"""

N, X, M = map(int,input().split())
mod_set = {X}
mod_lis = [X]
A = [0]*(10**5+1)
A[0] = X
for i in range(1,N):
    tmp = A[i-1]**2%M
    if tmp in mod_set:
        break
    A[i] = tmp
    mod_set.add(tmp)
    mod_lis.append(tmp)

j = mod_lis.index(tmp)
T = i - j
ans = 0
if T != 0:  
    ans += sum(mod_lis[:j])
    T_sum = sum(mod_lis[j:i])
    ans += T_sum * (N-j)//T
    T_lis = mod_lis[j:i]    
    ans += sum(T_lis[:(N-j)%T])
else:
    ans = sum(mod_lis)
#print(T_lis)
print(ans)
#print(T_sum)
#print(sum(T_lis))


Fixed submission:
# -*- coding: utf-8 -*-
"""
Created on Sat Sep 19 22:58:03 2020

@author: liang
"""

N,X,M=map(int,input().split())
a = X
hist = [a]
indices = [-1]*M
indices[a] = 0
flag=0
for i in range(1,min(10**6,N)):
  a = a**2 % M
  if indices[a] != -1:
    idx = indices[a]
    flag=1
    break
  hist.append(a)
  indices[a] = i
  
if flag==0:
  print(sum(hist))
  exit()
  
cycle = hist[idx:]
margin = hist[:idx]
q,r = divmod((N-len(margin)),len(cycle))
ans = 0
ans += sum(margin)
ans += sum(cycle)*q
#print(q,sum(cycle))
ans += sum(cycle[:r])
#print(r)
#print(cycle[:10])
print(ans)