#include <bits/stdc++.h>
using namespace std;
#define int long long

signed main () {
	int n,a,b;
	scanf("%lld%lld%lld",&n,&a,&b);
	if (a > b || (b - a) > n) {
		printf("0");
		return 0;
	}
	int minn = a * (n - 1) + b,maxn = b * (n - 1) + a;
	printf("%lld",maxn - minn + 1);
	return 0;
}