#include<bits/stdc++.h>
using namespace std;
int main(){
	int n,l,r,max=0;
	scanf("%d",&n);
	scanf("%d",&l); 
	scanf("%d",&r);  
	for(;l<=r;l++){
		int q=l;
		q%=n;
		if(q>max) max=q;
	}
	printf("%d",max);
	return 0;
}
/**************************************************************
	Problem: 2401
	User: houshanglin
	Language: C
	Result: Compile Error
****************************************************************/