#include <stdio.h>
int main (void){
float X,Y,R;
printf ("%s", "scan X and Y ->");
scanf ("%f%f", &X, &Y);
printf ("%s", "scan R ->");
scanf ("%f", &R);
R=(R*R)/2.;
R-=X*X+Y*Y;
if (R==0) printf ("%s\n", "YES");
else printf ("%s\n", "NO");
}