Buggy python submission (verdict: Time Limit Exceeded):
N, M = map(int, input().split())
S = input()
T = input()
def gcd(a, b):
	while b:
		a, b = b, a % b
	return a
 
def lcm(x, y):
    return (x * y) // gcd(x, y)
X = lcm(N ,M)
 
if S[0] != T[0]:
    print(-1)
elif X == N*M:
    print(N*M)
else:
    for i in range(1,(N*M//X)+1):
        L = X * i
        match = lcm(  L // N,  L // M)
        for j in range( (L // match)-1 ,0,-1):
            if S[j * N * match // L] != T[ j * M * match // L]:
                L = -1
                break
        if L == X * i:
            break
    print(L)

Fixed submission:
N, M = map(int, input().split())
S = str(input())
T = str(input())
def gcd(a, b):
	while b:
		a, b = b, a % b
	return a
 
def lcm(x, y):
    return (x * y) // gcd(x, y)
X = lcm(N ,M)
 
if S[0] != T[0]:
    print(-1)
elif X == N*M:
    print(N*M)
else:
        L = X
        match = lcm(  L // N,  L // M)
        for j in range(1, (L // match) ):
            if S[j * N * match // L] != T[ j * M * match // L]:
                L = -1
                break
        if L == X :
            print(L)
        else:
            print(-1)

Buggy python submission (verdict: Time Limit Exceeded):
N, M = map(int, input().split())
S = str(input())
T = str(input())
def gcd(a, b):
	while b:
		a, b = b, a % b
	return a
 
X = N*M // gcd(N,M)
 
if S[0] != T[0]:
    print(-1)
elif X == N * M:
    print(X)
else:
    for i in range(1,(N*M//X)+1):
        L = X * i
        m = gcd(  L // N,  L // M)
        for j in range(1, (N*M*m//L) ):
            if S[j * L // M // m] != T[ j * L // N // m ]:
                L = -1
                break
        if L == X * i:
            break
    print(L)

Fixed submission:
N, M = map(int, input().split())
S = str(input())
T = str(input())
def gcd(a, b):
	while b:
		a, b = b, a % b
	return a
 
def lcm(x, y):
    return (x * y) // gcd(x, y)
X = lcm(N ,M)
 
if S[0] != T[0]:
    print(-1)
elif X == N*M:
    print(N*M)
else:
        L = X
        match = lcm(  L // N,  L // M)
        for j in range(1, (L // match) ):
            if S[j * N * match // L] != T[ j * M * match // L]:
                L = -1
                break
        if L == X :
            print(L)
        else:
            print(-1)

Buggy python submission (verdict: Time Limit Exceeded):
N, M = map(int, input().split())
S = str(input())
T = str(input())
def gcd(a, b):
	while b:
		a, b = b, a % b
	return a
 
def lcm(x, y):
    return (x * y) // gcd(x, y)
X = lcm(N ,M)
 
if S[0] != T[0]:
    print(-1)
elif X == N*M:
    print(N*M)
else:
    for i in range(1,(N*M//X)+1):
        L = X * i
        m = lcm(  L // N,  L // M)
        for j in range(1, (L // m) ):
            if S[j * N * m // L] != T[ j * M * m // L]:
                L = -1
                break
        if L == X * i:
            break
    print(L)

Fixed submission:
N, M = map(int, input().split())
S = str(input())
T = str(input())
def gcd(a, b):
	while b:
		a, b = b, a % b
	return a
 
def lcm(x, y):
    return (x * y) // gcd(x, y)
X = lcm(N ,M)
 
if S[0] != T[0]:
    print(-1)
elif X == N*M:
    print(N*M)
else:
        L = X
        match = lcm(  L // N,  L // M)
        for j in range(1, (L // match) ):
            if S[j * N * match // L] != T[ j * M * match // L]:
                L = -1
                break
        if L == X :
            print(L)
        else:
            print(-1)

Buggy python submission (verdict: Time Limit Exceeded):
N, M = map(int, input().split())
S = input()
T = input()
def gcd(a, b):
	while b:
		a, b = b, a % b
	return a

def lcm(x, y):
    return (x * y) // gcd(x, y)
X = lcm(N ,M)

if S[0] != T[0]:
    print(-1)
elif X == N*M:
    print(N*M)
else:
    for i in range(1,(N*M//X)+1):
        L = X * i
        match = lcm(  L // N,  L // M)
        for j in range(1, (L // match) ):
            if S[j * N * match // L] != T[ j * M * match // L]:
                L = -1
                break
        if L == X * i:
            break
    print(L)

Fixed submission:
N, M = map(int, input().split())
S = str(input())
T = str(input())
def gcd(a, b):
	while b:
		a, b = b, a % b
	return a
 
def lcm(x, y):
    return (x * y) // gcd(x, y)
X = lcm(N ,M)
 
if S[0] != T[0]:
    print(-1)
elif X == N*M:
    print(N*M)
else:
        L = X
        match = lcm(  L // N,  L // M)
        for j in range(1, (L // match) ):
            if S[j * N * match // L] != T[ j * M * match // L]:
                L = -1
                break
        if L == X :
            print(L)
        else:
            print(-1)

Buggy python submission (verdict: Time Limit Exceeded):
N, M = map(int, input().split())
S = str(input())
T = str(input())
def gcd(a, b):
	while b:
		a, b = b, a % b
	return a

def lcm(x, y):
    return (x * y) // gcd(x, y)
X = lcm(N ,M)

if S[0] != T[0]:
    print(-1)
elif X == N*M:
    print(N*M)
else:
    for i in range(1,(N*M//X)+1):
        L = X * i
        match = lcm(  L // N,  L // M)
        for j in range(1, (L // match) ):
            if S[j * N * match // L] != T[ j * M * match // L]:
                L = -1
                break
        if L == X * i:
            break
    print(L)





Fixed submission:
N, M = map(int, input().split())
S = str(input())
T = str(input())
def gcd(a, b):
	while b:
		a, b = b, a % b
	return a
 
def lcm(x, y):
    return (x * y) // gcd(x, y)
X = lcm(N ,M)
 
if S[0] != T[0]:
    print(-1)
elif X == N*M:
    print(N*M)
else:
        L = X
        match = lcm(  L // N,  L // M)
        for j in range(1, (L // match) ):
            if S[j * N * match // L] != T[ j * M * match // L]:
                L = -1
                break
        if L == X :
            print(L)
        else:
            print(-1)

Buggy python submission (verdict: Time Limit Exceeded):
import math
N, M = map(int, input().split())
S = str(input())
T = str(input())
def gcd(a, b):
	while b:
		a, b = b, a % b
	return a

def lcm(x, y):
    return (x * y) // gcd(x, y)
X = lcm(N ,M)

if S[0] != T[0]:
    print(-1)
elif X == N*M:
    print(N*M)
else:
    for i in range(1,(N*M//X)+1):
        L = X * i
        counter = L
        y = L // N
        z = L // M
        match = lcm( y, z)
        for j in range(1, (L // match) ):
            if S[j * N * match // L] != T[ j * M * match // L]:
                counter = -1
                break
        if counter == L:
            break
    print(counter)

Fixed submission:
N, M = map(int, input().split())
S = str(input())
T = str(input())
def gcd(a, b):
	while b:
		a, b = b, a % b
	return a
 
def lcm(x, y):
    return (x * y) // gcd(x, y)
X = lcm(N ,M)
 
if S[0] != T[0]:
    print(-1)
elif X == N*M:
    print(N*M)
else:
        L = X
        match = lcm(  L // N,  L // M)
        for j in range(1, (L // match) ):
            if S[j * N * match // L] != T[ j * M * match // L]:
                L = -1
                break
        if L == X :
            print(L)
        else:
            print(-1)

Buggy python submission (verdict: Time Limit Exceeded):
N, M = map(int, input().split())
S = str(input())
T = str(input())

def lcm(x, y):
    def gcd(a, b):
        while b:
            a, b = b, a % b
        return a
    return (x * y) // gcd(x, y)
X = lcm(N ,M)

if S[0] != T[0]:
    print(-1)
elif X == N*M:
    print(N*M)
else:
    for i in range(1,(N*M//X)+1):
        L = X * i
        counter = L
        y = L // N
        z = L // M
        match = lcm( y, z)
        for j in range(1, (L // match) ):
            if S[j * N * match // L] != T[ j * M * match // L]:
                counter = -1
                break
        if counter == L:
            break
    print(counter)




Fixed submission:
N, M = map(int, input().split())
S = str(input())
T = str(input())
def gcd(a, b):
	while b:
		a, b = b, a % b
	return a
 
def lcm(x, y):
    return (x * y) // gcd(x, y)
X = lcm(N ,M)
 
if S[0] != T[0]:
    print(-1)
elif X == N*M:
    print(N*M)
else:
        L = X
        match = lcm(  L // N,  L // M)
        for j in range(1, (L // match) ):
            if S[j * N * match // L] != T[ j * M * match // L]:
                L = -1
                break
        if L == X :
            print(L)
        else:
            print(-1)

Buggy python submission (verdict: Runtime Error):
N, M = map(int, input().split())
S = str(input())
T = str(input())

def lcm(x, y):
    def gcd(a, b):
        while b:
            a, b = b, a % b
        return a
    return (x * y) // gcd(x, y)
X = lcm(N ,M)

if S[0] != T[0]:
    print(-1)
elif X == N*M:
    print(N*M)
else:
    for i in range(1,(N*M//X)+1):
        L = X * i
        counter = L
        y = L // N
        z = L // M
        match = lcm( y, z)
        for j in range(1, (L // match) ):
            if S[j * N * match // L] != T[l = j * M * match // L]:
                counter = -1
                break
        if counter == L:
            break
    print(counter)




Fixed submission:
N, M = map(int, input().split())
S = str(input())
T = str(input())
def gcd(a, b):
	while b:
		a, b = b, a % b
	return a
 
def lcm(x, y):
    return (x * y) // gcd(x, y)
X = lcm(N ,M)
 
if S[0] != T[0]:
    print(-1)
elif X == N*M:
    print(N*M)
else:
        L = X
        match = lcm(  L // N,  L // M)
        for j in range(1, (L // match) ):
            if S[j * N * match // L] != T[ j * M * match // L]:
                L = -1
                break
        if L == X :
            print(L)
        else:
            print(-1)

Buggy python submission (verdict: Time Limit Exceeded):
N, M = map(int, input().split())
S = str(input())
T = str(input())

def lcm(x, y):
    def gcd(a, b):
        while b:
            a, b = b, a % b
        return a
    return (x * y) // gcd(x, y)
X = lcm(N ,M)

if S[0] != T[0]:
    print(-1)
elif X == N*M:
    print(N*M)

else:
    for i in range(1,(N*M//X)+1):
        L = X * i
        counter = L
        y = L // N
        z = L // M
        match = lcm( y, z)
        for j in range(1, (L // match) ):
            k = j * N * match // L
            l = j * M * match // L
            if S[k] != T[l]:
                counter = -1
        if counter == L:
            break
    print(counter)


Fixed submission:
N, M = map(int, input().split())
S = str(input())
T = str(input())
def gcd(a, b):
	while b:
		a, b = b, a % b
	return a
 
def lcm(x, y):
    return (x * y) // gcd(x, y)
X = lcm(N ,M)
 
if S[0] != T[0]:
    print(-1)
elif X == N*M:
    print(N*M)
else:
        L = X
        match = lcm(  L // N,  L // M)
        for j in range(1, (L // match) ):
            if S[j * N * match // L] != T[ j * M * match // L]:
                L = -1
                break
        if L == X :
            print(L)
        else:
            print(-1)