#include <bits/stdc++.h>
using namespace std;
int main()
{
int n;
//cout << "Nhap N: ";
cin >> n;
int m=n;
while(m>10)
{
m=0;
while(n>0)
{
m = m + pow((n%10),2);
n/=10;
}
n=m;
}
cout << m;
return 0;
}
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