题解

#include <bits/stdc++.h>
using namespace std;

int main(){
    int a,b,c,d,e = 0;
    cin >> a >> b >> c >> d;
    if(a + b + c + d == 0){
        e = 0;
    }else if(a + b + c + d == 1){
        e = 1;
    }else if(a + b + c + d == 2){
        e = 2;
    }else if(a + b + c + d == 3){
        e = 1;
    }else if(a + b + c + d == 4){
        e = 0;
    } 
    cout << e;
    return 0;
}