#include <iostream>
#include <string>
using namespace std;
int EUC(int a,int b)
{
int buff = 0;
if(b < a)
{
buff = a;
a = b;
b = buff;
}
b = b - a;
return b;
}
int main()
{
int a = 0;
int b = 0;
cin >> a >> b;
while(a % b != 0)
{
b = EUC(a,b);
}
cout << b;
return 0;
}
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