#include<bits/stdc++.h>
using namespace std;
int main() {
	int a,b,c,d,h;
	scanf("%d%d%d%d",&a,&b,&c,&d);
	h=a+b+c+d;
	printf("%d",h);
    return 0;
}

/**************************************************************
	Problem: 1390
	User: huangcanwu
	Language: C++
	Result: Wrong Answer
****************************************************************/