#include <bits/stdc++.h>
using namespace std;
//--------------------------------------------
#define FOR(i,a,b) for(int i=(a);i<(b);i++)
#define RFOR(i,a,b) for(int i=(b)-1;i>=(a);i--)
#define REP(i,n) FOR(i,0,n)
#define RREP(i,n) RFOR(i,0,n)
#define LL long long
#define INF INT_MAX/3
//--------------------------------------------
const double EPS = 1e-14;
const double PI = acos(-1.0);
//--------------------------------------------
int main(){
int n, a, b;
scanf("%d %d %d",&n, &a, &b);
if (a <= b && n != 1) {
printf("%d\n",max(0, (a + (n - 1) * b) - ((n - 1) * a + b) + 1));
} else if (n == 1 && a == b) {
printf("1\n");
} else {
printf("0\n");
}
}