#include <iostream>
#include<string.h>
using namespace std;
int main()
{
    int n,a,b;
    cin>>n>>a>>b;
    if(n==1)
    {
        cout<<a<<endl;
        return 0;
    }
    else if(n==2)
    {
        cout<<a+b<<endl;
        return 0;
    }
    n-=2;
    int z1=n*a;
    int z2=n*b;
    cout<<z2-z1+1<<endl;

}
