char x='y';
    int m, n;
    while(x=='y'){
        cout<<"Enter numbers (m,n):";
        cin>>m;
        cin.ignore();
        cin>>n;
        cout<<"GCD of "<<m<<" and "<<n<<" is "<<GCD(m,n)<<endl;
        cout<<"Run again? y/n ";
        cin>>x;
    }

int GCD(int m, int n) {
    if (n==0){
        return m;
    }else {
        return GCD(n, m%n);
    }
}