#include <cstdio>
int main(void)
{
int A,B,N;
scanf("%d%d%d",&N,&A,&B);
if(N==1)
{
if(A==B)
printf("1\n");
else
printf("0\n");
}
else
{
if(A>B)
printf("0\n");
else
printf("%lld\n",(long long )(B-A)*(N-2)+1);
}
return 0;
}