#include<bits/stdc++.h>
using namespace std;
long long a,b,ans=0,c;
int main(){
     //freopen("candy.in","r",stdin);
    //freopen("candy.out","w",stdout);
    cin>>a>>b>>c;
    for(int i=b;i<=c;i++){
        if(i%a>ans) ans=i%a;
    }
    cout<<ans;
    return 0;
}