uva 264 Count on Cantor

#include<bits/stdc++.h>
using namespace std;

int main()
{
    long long a,b,k,n;
    while(cin>>n)
    {
        printf("TERM %lld IS ",n);
        for(k=1; k*(k+1)<=2*n; ++k);
        --k;
        n-=(k*(k+1)/2);
        if(k&1)
        {
            a=1;
            b=n?k+1:k;
            for(int i=2; i<=n; ++i) ++a,--b;
        }
        else
        {
            a=n?k+1:k,b=1;
            for(int i=2; i<=n; ++i)--a,++b;

        }
        printf("%lld/%lld\n",a,b);
    }
    return 0;
}