#include <iostream>  
using namespace std;  

int main() {  
    int math, chinese, english;  
    // 输入三科成绩  
    cin >> math >> chinese >> english;  

    // 计算平均分  
    double average = (math + chinese + english) / 3.0;  

    // 判断平均分是否低于60  
    if (average < 60) {  
        cout << "YES" << endl;  
    } else {  
        cout << "NO" << endl;  
    }  

    return 0;  
}