#include <stdio.h>
#include <stdlib.h>

int main()
{
    int sht,lng,i,sum;
    scanf("%d %d %d",&i,&sht,&lng);
    if(i < 1)
    {
        printf("0\n");
        return 0;
    }
    if(sht > 10e9||lng > 10e9)
    {
        printf("0\n");
        return 0;
    }
    if(i == 1 )
    {
        if(sht == lng)
            sum = 1;
        else
            sum = 0;
    }
    else
        sum = (sht + lng * (i - 1)) - (sht * (i - 1) + lng) + 1;
    printf("%d\n",sum);
    return 0;
}
