Buggy python submission (verdict: Time Limit Exceeded):
import math, string, itertools, fractions, heapq, collections, re,  array, bisect, sys, random, time, copy, functools
sys.setrecursionlimit(10**7)
inf = 10 ** 20
eps = 1.0 / 10**10
mod = 10**9+7
dd = [(-1, 0), (0, 1), (1, 0), (0, -1)]
ddn = [(-1, 0), (-1, 1), (0, 1), (1, 1), (1, 0), (1, -1), (0, -1), (-1, -1)]
def LI(): return [int(x) for x in sys.stdin.readline().split()]
def LI_(): return [int(x)-1 for x in sys.stdin.readline().split()]
def LF(): return [float(x) for x in sys.stdin.readline().split()]
def LS(): return sys.stdin.readline().split()
def I(): return int(sys.stdin.readline())
def F(): return float(sys.stdin.readline())
def pf(s): return print(s, flush=True)

def lcm(x, y):
    return (x * y) // fractions.gcd(x, y)

N, M = LI()
S = input()
T = input()

#  N, M = 10**5, 10**5
#  S = 's'*N
#  T = 't'*M

X = lcm(N, M)
L = X
XS = ['X' for i in range(L+1)]
XT = ['X' for i in range(L+1)]
count = 0
LN = L/N
while True:
    XS[int(count*LN)] = S[count]
    count += 1
    if count > N-1:
        break

count = 0
LM = L/M
while True:
    XT[int(count*LM)] = T[count]
    count += 1
    if count > M-1:
        break

#  print(XS, XT)
for i in range(0, L+1):
    if XS[i] != 'X' and XT[i] != 'X':
        if XT[i] != XS[i]:
            print(-1)
            exit()
print(L)


Fixed submission:
import math, string, itertools, fractions, heapq, collections, re,  array, bisect, sys, random, time, copy, functools
sys.setrecursionlimit(10**7)
inf = 10 ** 20
eps = 1.0 / 10**10
mod = 10**9+7
dd = [(-1, 0), (0, 1), (1, 0), (0, -1)]
ddn = [(-1, 0), (-1, 1), (0, 1), (1, 1), (1, 0), (1, -1), (0, -1), (-1, -1)]
def LI(): return [int(x) for x in sys.stdin.readline().split()]
def LI_(): return [int(x)-1 for x in sys.stdin.readline().split()]
def LF(): return [float(x) for x in sys.stdin.readline().split()]
def LS(): return sys.stdin.readline().split()
def I(): return int(sys.stdin.readline())
def F(): return float(sys.stdin.readline())
def pf(s): return print(s, flush=True)

def lcm(x, y):
    return (x * y) // fractions.gcd(x, y)

N, M = LI()
S = input()
T = input()

#  N, M = 10**5, 10**5
#  S = 's'*N
#  T = 't'*M

X = lcm(N, M)
L = X
#  XS = ['X' for i in range(L+1)]
#  XT = ['X' for i in range(L+1)]
XS, XT = {}, {}
count = 0
LN = L/N
while True:
    XS[int(count*LN)] = S[count]
    count += 1
    if count > N-1:
        break

count = 0
LM = L/M
while True:
    XT[int(count*LM)] = T[count]
    count += 1
    if count > M-1:
        break

for key, value in XS.items():
    #  print(key, value)
    if key in XT:
        if value != XT[key]:
            print(-1)
            exit()
#  print(XS, XT)
#  for i in range(0, L+1):
#      if XS[i] != 'X' and XT[i] != 'X':
#          if XT[i] != XS[i]:
#              print(-1)
#              exit()
print(L)

Buggy python submission (verdict: Runtime Error):
import math, string, itertools, fractions, heapq, collections, re,  array, bisect, sys, random, time, copy, functools
sys.setrecursionlimit(10**7)
inf = 10 ** 20
eps = 1.0 / 10**10
mod = 10**9+7
dd = [(-1, 0), (0, 1), (1, 0), (0, -1)]
ddn = [(-1, 0), (-1, 1), (0, 1), (1, 1), (1, 0), (1, -1), (0, -1), (-1, -1)]
def LI(): return [int(x) for x in sys.stdin.readline().split()]
def LI_(): return [int(x)-1 for x in sys.stdin.readline().split()]
def LF(): return [float(x) for x in sys.stdin.readline().split()]
def LS(): return sys.stdin.readline().split()
def I(): return int(sys.stdin.readline())
def F(): return float(sys.stdin.readline())
def pf(s): return print(s, flush=True)

def lcm(x, y):
    return (x * y) // math.gcd(x, y)

N, M = LI()
S = input()
T = input()
#  N, M = 10**5, 10**5
#  S = 's'*N
#  T = 't'*M

math.gcd(18,4)
print(32131)

Fixed submission:
import math, string, itertools, fractions, heapq, collections, re,  array, bisect, sys, random, time, copy, functools
sys.setrecursionlimit(10**7)
inf = 10 ** 20
eps = 1.0 / 10**10
mod = 10**9+7
dd = [(-1, 0), (0, 1), (1, 0), (0, -1)]
ddn = [(-1, 0), (-1, 1), (0, 1), (1, 1), (1, 0), (1, -1), (0, -1), (-1, -1)]
def LI(): return [int(x) for x in sys.stdin.readline().split()]
def LI_(): return [int(x)-1 for x in sys.stdin.readline().split()]
def LF(): return [float(x) for x in sys.stdin.readline().split()]
def LS(): return sys.stdin.readline().split()
def I(): return int(sys.stdin.readline())
def F(): return float(sys.stdin.readline())
def pf(s): return print(s, flush=True)

def lcm(x, y):
    return (x * y) // fractions.gcd(x, y)

N, M = LI()
S = input()
T = input()

#  N, M = 10**5, 10**5
#  S = 's'*N
#  T = 't'*M

X = lcm(N, M)
L = X
#  XS = ['X' for i in range(L+1)]
#  XT = ['X' for i in range(L+1)]
XS, XT = {}, {}
count = 0
LN = L/N
while True:
    XS[int(count*LN)] = S[count]
    count += 1
    if count > N-1:
        break

count = 0
LM = L/M
while True:
    XT[int(count*LM)] = T[count]
    count += 1
    if count > M-1:
        break

for key, value in XS.items():
    #  print(key, value)
    if key in XT:
        if value != XT[key]:
            print(-1)
            exit()
#  print(XS, XT)
#  for i in range(0, L+1):
#      if XS[i] != 'X' and XT[i] != 'X':
#          if XT[i] != XS[i]:
#              print(-1)
#              exit()
print(L)

Buggy python submission (verdict: Runtime Error):
import math, string, itertools, fractions, heapq, collections, re,  array, bisect, sys, random, time, copy, functools
sys.setrecursionlimit(10**7)
inf = 10 ** 20
eps = 1.0 / 10**10
mod = 10**9+7
dd = [(-1, 0), (0, 1), (1, 0), (0, -1)]
ddn = [(-1, 0), (-1, 1), (0, 1), (1, 1), (1, 0), (1, -1), (0, -1), (-1, -1)]
def LI(): return [int(x) for x in sys.stdin.readline().split()]
def LI_(): return [int(x)-1 for x in sys.stdin.readline().split()]
def LF(): return [float(x) for x in sys.stdin.readline().split()]
def LS(): return sys.stdin.readline().split()
def I(): return int(sys.stdin.readline())
def F(): return float(sys.stdin.readline())
def pf(s): return print(s, flush=True)

def lcm(x, y):
    return (x * y) // math.gcd(x, y)

N, M = LI()
S = input()
T = input()
#  N, M = 10**5, 10**5
#  S = 's'*N
#  T = 't'*M

X = lcm(N, M)
print(32131)

Fixed submission:
import math, string, itertools, fractions, heapq, collections, re,  array, bisect, sys, random, time, copy, functools
sys.setrecursionlimit(10**7)
inf = 10 ** 20
eps = 1.0 / 10**10
mod = 10**9+7
dd = [(-1, 0), (0, 1), (1, 0), (0, -1)]
ddn = [(-1, 0), (-1, 1), (0, 1), (1, 1), (1, 0), (1, -1), (0, -1), (-1, -1)]
def LI(): return [int(x) for x in sys.stdin.readline().split()]
def LI_(): return [int(x)-1 for x in sys.stdin.readline().split()]
def LF(): return [float(x) for x in sys.stdin.readline().split()]
def LS(): return sys.stdin.readline().split()
def I(): return int(sys.stdin.readline())
def F(): return float(sys.stdin.readline())
def pf(s): return print(s, flush=True)

def lcm(x, y):
    return (x * y) // fractions.gcd(x, y)

N, M = LI()
S = input()
T = input()

#  N, M = 10**5, 10**5
#  S = 's'*N
#  T = 't'*M

X = lcm(N, M)
L = X
#  XS = ['X' for i in range(L+1)]
#  XT = ['X' for i in range(L+1)]
XS, XT = {}, {}
count = 0
LN = L/N
while True:
    XS[int(count*LN)] = S[count]
    count += 1
    if count > N-1:
        break

count = 0
LM = L/M
while True:
    XT[int(count*LM)] = T[count]
    count += 1
    if count > M-1:
        break

for key, value in XS.items():
    #  print(key, value)
    if key in XT:
        if value != XT[key]:
            print(-1)
            exit()
#  print(XS, XT)
#  for i in range(0, L+1):
#      if XS[i] != 'X' and XT[i] != 'X':
#          if XT[i] != XS[i]:
#              print(-1)
#              exit()
print(L)

Buggy python submission (verdict: Runtime Error):
import math, string, itertools, fractions, heapq, collections, re,  array, bisect, sys, random, time, copy, functools
sys.setrecursionlimit(10**7)
inf = 10 ** 20
eps = 1.0 / 10**10
mod = 10**9+7
dd = [(-1, 0), (0, 1), (1, 0), (0, -1)]
ddn = [(-1, 0), (-1, 1), (0, 1), (1, 1), (1, 0), (1, -1), (0, -1), (-1, -1)]
def LI(): return [int(x) for x in sys.stdin.readline().split()]
def LI_(): return [int(x)-1 for x in sys.stdin.readline().split()]
def LF(): return [float(x) for x in sys.stdin.readline().split()]
def LS(): return sys.stdin.readline().split()
def I(): return int(sys.stdin.readline())
def F(): return float(sys.stdin.readline())
def pf(s): return print(s, flush=True)

def lcm(x, y):
    return (x * y) // math.gcd(x, y)

N, M = LI()
S = input()
T = input()
#  N, M = 10**5, 10**5
#  S = 's'*N
#  T = 't'*M

X = lcm(N, M)
L = X
XS = ['X' for i in range(L+1)]
XT = ['X' for i in range(L+1)]
print(122232)

Fixed submission:
import math, string, itertools, fractions, heapq, collections, re,  array, bisect, sys, random, time, copy, functools
sys.setrecursionlimit(10**7)
inf = 10 ** 20
eps = 1.0 / 10**10
mod = 10**9+7
dd = [(-1, 0), (0, 1), (1, 0), (0, -1)]
ddn = [(-1, 0), (-1, 1), (0, 1), (1, 1), (1, 0), (1, -1), (0, -1), (-1, -1)]
def LI(): return [int(x) for x in sys.stdin.readline().split()]
def LI_(): return [int(x)-1 for x in sys.stdin.readline().split()]
def LF(): return [float(x) for x in sys.stdin.readline().split()]
def LS(): return sys.stdin.readline().split()
def I(): return int(sys.stdin.readline())
def F(): return float(sys.stdin.readline())
def pf(s): return print(s, flush=True)

def lcm(x, y):
    return (x * y) // fractions.gcd(x, y)

N, M = LI()
S = input()
T = input()

#  N, M = 10**5, 10**5
#  S = 's'*N
#  T = 't'*M

X = lcm(N, M)
L = X
#  XS = ['X' for i in range(L+1)]
#  XT = ['X' for i in range(L+1)]
XS, XT = {}, {}
count = 0
LN = L/N
while True:
    XS[int(count*LN)] = S[count]
    count += 1
    if count > N-1:
        break

count = 0
LM = L/M
while True:
    XT[int(count*LM)] = T[count]
    count += 1
    if count > M-1:
        break

for key, value in XS.items():
    #  print(key, value)
    if key in XT:
        if value != XT[key]:
            print(-1)
            exit()
#  print(XS, XT)
#  for i in range(0, L+1):
#      if XS[i] != 'X' and XT[i] != 'X':
#          if XT[i] != XS[i]:
#              print(-1)
#              exit()
print(L)

Buggy python submission (verdict: Time Limit Exceeded):
import math, string, itertools, fractions, heapq, collections, re,  array, bisect, sys, random, time, copy, functools
sys.setrecursionlimit(10**7)
inf = 10 ** 20
eps = 1.0 / 10**10
mod = 10**9+7
dd = [(-1, 0), (0, 1), (1, 0), (0, -1)]
ddn = [(-1, 0), (-1, 1), (0, 1), (1, 1), (1, 0), (1, -1), (0, -1), (-1, -1)]
def LI(): return [int(x) for x in sys.stdin.readline().split()]
def LI_(): return [int(x)-1 for x in sys.stdin.readline().split()]
def LF(): return [float(x) for x in sys.stdin.readline().split()]
def LS(): return sys.stdin.readline().split()
def I(): return int(sys.stdin.readline())
def F(): return float(sys.stdin.readline())
def pf(s): return print(s, flush=True)

def gcd(a,b):
    """Compute the greatest common divisor of a and b"""
    while b > 0:
        a, b = b, a % b
    return a
    
def lcm(a, b):
    """Compute the lowest common multiple of a and b"""
    return int(a * b / gcd(a, b))


N, M = LI()
S = input()
T = input()
#  N, M = 10**5, 10**5
#  S = 's'*N
#  T = 't'*M

X = lcm(len(S), len(T))
L = X
XS = ['X' for i in range(L+1)]
XT = ['X' for i in range(L+1)]
count = 0
LN = L/N
while True:
    XS[int(count*LN)] = S[count]
    count += 1
    if count > N-1:
        break

count = 0
LM = L/M
while True:
    XT[int(count*LM)] = T[count]
    count += 1
    if count > M-1:
        break

#  print(XS, XT)
for i in range(0, L+1):
    if XS[i] != 'X' and XT[i] != 'X':
        if XT[i] != XS[i]:
            print(-1)
            exit()
print(L)


Fixed submission:
import math, string, itertools, fractions, heapq, collections, re,  array, bisect, sys, random, time, copy, functools
sys.setrecursionlimit(10**7)
inf = 10 ** 20
eps = 1.0 / 10**10
mod = 10**9+7
dd = [(-1, 0), (0, 1), (1, 0), (0, -1)]
ddn = [(-1, 0), (-1, 1), (0, 1), (1, 1), (1, 0), (1, -1), (0, -1), (-1, -1)]
def LI(): return [int(x) for x in sys.stdin.readline().split()]
def LI_(): return [int(x)-1 for x in sys.stdin.readline().split()]
def LF(): return [float(x) for x in sys.stdin.readline().split()]
def LS(): return sys.stdin.readline().split()
def I(): return int(sys.stdin.readline())
def F(): return float(sys.stdin.readline())
def pf(s): return print(s, flush=True)

def lcm(x, y):
    return (x * y) // fractions.gcd(x, y)

N, M = LI()
S = input()
T = input()

#  N, M = 10**5, 10**5
#  S = 's'*N
#  T = 't'*M

X = lcm(N, M)
L = X
#  XS = ['X' for i in range(L+1)]
#  XT = ['X' for i in range(L+1)]
XS, XT = {}, {}
count = 0
LN = L/N
while True:
    XS[int(count*LN)] = S[count]
    count += 1
    if count > N-1:
        break

count = 0
LM = L/M
while True:
    XT[int(count*LM)] = T[count]
    count += 1
    if count > M-1:
        break

for key, value in XS.items():
    #  print(key, value)
    if key in XT:
        if value != XT[key]:
            print(-1)
            exit()
#  print(XS, XT)
#  for i in range(0, L+1):
#      if XS[i] != 'X' and XT[i] != 'X':
#          if XT[i] != XS[i]:
#              print(-1)
#              exit()
print(L)

Buggy python submission (verdict: Time Limit Exceeded):
import math, string, itertools, fractions, heapq, collections, re,  array, bisect, sys, random, time, copy, functools
sys.setrecursionlimit(10**7)
inf = 10 ** 20
eps = 1.0 / 10**10
mod = 10**9+7
dd = [(-1, 0), (0, 1), (1, 0), (0, -1)]
ddn = [(-1, 0), (-1, 1), (0, 1), (1, 1), (1, 0), (1, -1), (0, -1), (-1, -1)]
def LI(): return [int(x) for x in sys.stdin.readline().split()]
def LI_(): return [int(x)-1 for x in sys.stdin.readline().split()]
def LF(): return [float(x) for x in sys.stdin.readline().split()]
def LS(): return sys.stdin.readline().split()
def I(): return int(sys.stdin.readline())
def F(): return float(sys.stdin.readline())
def pf(s): return print(s, flush=True)

def gcd(a,b):
    """Compute the greatest common divisor of a and b"""
    while b > 0:
        a, b = b, a % b
    return a
    
def lcm(a, b):
    """Compute the lowest common multiple of a and b"""
    return int(a * b / gcd(a, b))


N, M = LI()
S = input()
T = input()
#  N, M = 10**5, 10**5
#  S = 's'*N
#  T = 't'*M

X = lcm(len(S), len(T))
L = X
XS = ['X' for i in range(L+1)]
XT = ['X' for i in range(L+1)]
count = 0
LN = L/N
while True:
    XS[int(count*LN)] = S[count]
    count += 1
    if count > N-1:
        break

count = 0
LM = L/M
while True:
    XT[int(count*LM)] = T[count]
    count += 1
    if count > M-1:
        break

#  print(XS, XT)
for i in range(0, L+1):
    if XS[i] != 'X' and XT[i] != 'X':
        if XT[i] != XS[i]:
            print(-1)
            exit()
print(L)

				

Fixed submission:
import math, string, itertools, fractions, heapq, collections, re,  array, bisect, sys, random, time, copy, functools
sys.setrecursionlimit(10**7)
inf = 10 ** 20
eps = 1.0 / 10**10
mod = 10**9+7
dd = [(-1, 0), (0, 1), (1, 0), (0, -1)]
ddn = [(-1, 0), (-1, 1), (0, 1), (1, 1), (1, 0), (1, -1), (0, -1), (-1, -1)]
def LI(): return [int(x) for x in sys.stdin.readline().split()]
def LI_(): return [int(x)-1 for x in sys.stdin.readline().split()]
def LF(): return [float(x) for x in sys.stdin.readline().split()]
def LS(): return sys.stdin.readline().split()
def I(): return int(sys.stdin.readline())
def F(): return float(sys.stdin.readline())
def pf(s): return print(s, flush=True)

def lcm(x, y):
    return (x * y) // fractions.gcd(x, y)

N, M = LI()
S = input()
T = input()

#  N, M = 10**5, 10**5
#  S = 's'*N
#  T = 't'*M

X = lcm(N, M)
L = X
#  XS = ['X' for i in range(L+1)]
#  XT = ['X' for i in range(L+1)]
XS, XT = {}, {}
count = 0
LN = L/N
while True:
    XS[int(count*LN)] = S[count]
    count += 1
    if count > N-1:
        break

count = 0
LM = L/M
while True:
    XT[int(count*LM)] = T[count]
    count += 1
    if count > M-1:
        break

for key, value in XS.items():
    #  print(key, value)
    if key in XT:
        if value != XT[key]:
            print(-1)
            exit()
#  print(XS, XT)
#  for i in range(0, L+1):
#      if XS[i] != 'X' and XT[i] != 'X':
#          if XT[i] != XS[i]:
#              print(-1)
#              exit()
print(L)

Buggy python submission (verdict: Time Limit Exceeded):
import math, string, itertools, fractions, heapq, collections, re,  array, bisect, sys, random, time, copy, functools
sys.setrecursionlimit(10**7)
inf = 10 ** 20
eps = 1.0 / 10**10
mod = 10**9+7
dd = [(-1, 0), (0, 1), (1, 0), (0, -1)]
ddn = [(-1, 0), (-1, 1), (0, 1), (1, 1), (1, 0), (1, -1), (0, -1), (-1, -1)]
def LI(): return [int(x) for x in sys.stdin.readline().split()]
def LI_(): return [int(x)-1 for x in sys.stdin.readline().split()]
def LF(): return [float(x) for x in sys.stdin.readline().split()]
def LS(): return sys.stdin.readline().split()
def I(): return int(sys.stdin.readline())
def F(): return float(sys.stdin.readline())
def pf(s): return print(s, flush=True)

def gcd(a,b):
    """Compute the greatest common divisor of a and b"""
    while b > 0:
        a, b = b, a % b
    return a
    
def lcm(a, b):
    """Compute the lowest common multiple of a and b"""
    return int(a * b / gcd(a, b))


N, M = LI()
S = input()
T = input()
N, M = len(S), len(T)

X = lcm(len(S), len(T))
L = X
XS = ['X' for i in range(L+1)]
XT = ['X' for i in range(L+1)]
count = 0
while True:
    XS[int(count*L/N)] = S[count]
    count += 1
    if count > N-1:
        break

count = 0
while True:
    XT[int(count*L/M)] = T[count]
    count += 1
    if count > M-1:
        break

#  print(XS, XT)
for i in range(0, L+1):
    if XS[i] != 'X' and XT[i] != 'X':
        if XT[i] != XS[i]:
            print(-1)
            exit()
print(L)


Fixed submission:
import math, string, itertools, fractions, heapq, collections, re,  array, bisect, sys, random, time, copy, functools
sys.setrecursionlimit(10**7)
inf = 10 ** 20
eps = 1.0 / 10**10
mod = 10**9+7
dd = [(-1, 0), (0, 1), (1, 0), (0, -1)]
ddn = [(-1, 0), (-1, 1), (0, 1), (1, 1), (1, 0), (1, -1), (0, -1), (-1, -1)]
def LI(): return [int(x) for x in sys.stdin.readline().split()]
def LI_(): return [int(x)-1 for x in sys.stdin.readline().split()]
def LF(): return [float(x) for x in sys.stdin.readline().split()]
def LS(): return sys.stdin.readline().split()
def I(): return int(sys.stdin.readline())
def F(): return float(sys.stdin.readline())
def pf(s): return print(s, flush=True)

def lcm(x, y):
    return (x * y) // fractions.gcd(x, y)

N, M = LI()
S = input()
T = input()

#  N, M = 10**5, 10**5
#  S = 's'*N
#  T = 't'*M

X = lcm(N, M)
L = X
#  XS = ['X' for i in range(L+1)]
#  XT = ['X' for i in range(L+1)]
XS, XT = {}, {}
count = 0
LN = L/N
while True:
    XS[int(count*LN)] = S[count]
    count += 1
    if count > N-1:
        break

count = 0
LM = L/M
while True:
    XT[int(count*LM)] = T[count]
    count += 1
    if count > M-1:
        break

for key, value in XS.items():
    #  print(key, value)
    if key in XT:
        if value != XT[key]:
            print(-1)
            exit()
#  print(XS, XT)
#  for i in range(0, L+1):
#      if XS[i] != 'X' and XT[i] != 'X':
#          if XT[i] != XS[i]:
#              print(-1)
#              exit()
print(L)