UVa Solution – 11417 – GCD

#include<stdio.h>

int main()
{
int N;
while(scanf("%d",&N)==1)
{
if(N==0)
    break;
int G=0,i,j;
for(i=1;i<N;i++)
{
for(j=i+1;j<=N;j++)
{
G+=GCD(i,j);
}
}
printf("%dn",G);
}
return 0;
}

int GCD(int a,int b)
{
    if(b==0)
        return a;
    return GCD(b,a%b);
}