北大OJ2407

#include<iostream>#include<cstdio>using namespace std;int main(){int n,i,j,number;while(scanf("%d",&n)!=EOF&&n){number=n;for(i=2;i<=n;i++){if(n%i==0){number=number/i*(i-1);while(n%i==0) n/=i;}}printf("%d\n",number);}return 0;}