#include <stdio.h>
#include <math.h>
int main(void){
    int x, y, r;
    int xdis, ydis, dis;
    int ans = 0;
    scanf( "%d %d %d", &x, &y, &r );
    xdis = x < 0 ? x * -1: x;
    ydis = y < 0 ? y * -1: y;
    ans = xdis + ydis + ceil( sqrt( 2 * r * r ) );
    printf( "%d\n", ans );
}