#include <stdio.h>
int func(int n,int r){
int sum=1;
if(r>0){
sum=func(n-1,r-1)*n/r;
}
return sum;
}
int main(void) {
int n,r;
printf("%dC%d=%d",n
,r
,func
(n
,r
)); return 0;
}
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