#include<iostream>
#include<cmath>
using namespace std;
int a,b,c,cnt=0;
int main(){
    cin>>a>>b>>c;
    while(1){
        if(c==0)
            break;
        if(min(a,b)==a)
            a++;
        else
            b++;
        c--;
    }
    int y=min(a,b),cnt=0,i=1;
    while(1){
        if(y<i){
            cout<<i;
            break;
        }
        else{
            i++;
            y-=i;
        }
    }
    return 0;
}

求hack