#179 triunghi

#include <iostream>

using namespace std;

int main()
{
    float a,b,c;
    cin>>a>>b>>c;
    if((a+c>b && b+c>a && a+b>c) && (a>0 && b>0 && c>0))
    cout<<"da";
    else
    cout<<"nu";
    return 0;
}