C++,codeforces,69A,Young Physicist

/*
codeforces,69A,Young Physicist
n个向量和是否为0,向量为(x,y,z)
第一行输入数字n
之后n行, 每行一个向量, 三个空格隔开的数字
输出YES或NO
和是0输出YES,否则输出NO
*/
#include <iostream>
int main(){
    int t;std::cin>>t;
    int x=0,y=0,z=0;
    while(t--){
        int a,b,c;
        std::cin>>a>>b>>c;
        x+=a;
        y+=b;
        z+=c;
    }
    if(x==0&&y==0&&z==0){
        std::cout<<"YES";
    }else{
        std::cout<<"NO";
    }
    return 0;
}