766A - Mahmoud and Longest Uncommon Subsequence

#include <iostream>

#include<vector>

#include<string>

#include<math.h>

#include<map>

#include<algorithm>

/***** S. M. Sabiul Hajjaj Sabit *****/

using namespace std;

template <typename T>long long int power(T a, T b)

{

    long long int pow=1;

    for(int i=0; i<b; i++)

    {

        pow *= a;

    }

    return pow;

}

///*********Write Code From Here*********///

int main()

{

    string a,b;

    cin>>a;

    cin>>b;

    if(a==b)

    {

        cout<<-1<<endl;

    }

    else

    {

      cout<<max(a.size(),b.size())<<endl;

    }

}