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

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