function Main(input) {
    var s = input;
    var k = input.length;
    var oCount = 0;
    var res;
    for(var i = 0; i < k; i++){
        if(s[i] == "o"){
            oCount++;
        }
    }
    if(oCount >= 8){
        res = "YES";
    }else{
        if(8 <= 15 - k + oCount){
            res = "YES";
        }else{
            res = "NO";
        }
    }
    console.log(res);
}
Main(require("fs").readFileSync("/dev/stdin", "utf8"));
