#include <iostream>
using namespace std;
int nod(int a, int b){
cout<<"OK";
int c=0;
while(a+b!=0){
if(a>b) a=a%b;else b=b%a;
c=a;a=b;b=c;}
return a+b;
}
int main()
{
nod(5,15);
return 0;
}
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