#include <stdio.h>
int binpow (int a, int n) {
if (n == 0)
return 1;
if (n % 2 == 1)
return binpow (a, n-1) * a;
else {
int b = binpow (a, n/2);
return b * b;
}
}
int main(){
int a;
int n;
int res;
res = binpow(a, n);
return 0;
}
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