// Wrongri-La Shower

// 45度回転

#include<cstdio>
#include<cmath>

typedef long long ll;

const double EPS = 1e-9;

int X, Y;
double R;

bool can(int k){
    return X-R > -k && k > X+R && Y-R > -k && k > Y+R;
}

int main(){
    scanf("%d %d %lf", &X, &Y, &R);
    {
        int x = X + Y, y = X - Y;
        X = x; Y = y;

        R *= std::sqrt(2);
    }

    int lb = X + Y, ub = 252521;
    while(ub - lb > 1){
        int mid = (lb+ub) / 2;
        if(can(mid)){
            ub = mid;
        }else{
            lb = mid;
        }
    }

    printf("%d\n", ub);
}