#include long f(long n){long i,p=1;for (i=2;i<=n;i++) p*=i;return p;}void main(){long m,n;printf("m=");scanf("%ld",&m);printf("n=");scanf("%ld",&n);if (m>n) printf("Error: m>n");else printf("c=%ld",f(n)/f(n-m)/f(m));}