Factorial of the smallest of first and last digits of a number in C++

#include <iostream>
#include <sstream>
using namespace std;
int main()
{
    string x , m;
    int s , result=1 , n;
    cout<<"Enter the number : ";
    cin>>x;
    s=x.size();
    if(x[0]>x[s-1])
    {
        m=x[s-1];
        stringstream a(m);
        a>>n;
    }
    else if(x[0]<x[s-1])
    {
        m=x[0];
        stringstream a(m);
        a>>n;
    }
    while(n>0)
    {
        result=result*n;
        n=n-1;
    }
    cout<<result;
}