function Main(inp) {
    var input = inp.split("\n");
    input = input[0].split(' ').map(function(n) { return Number(n);});
    var a = input[0];
    var b = input[1];
    console.log(Math.ceil((a + b) / 2));
}

Main(require("fs").readFileSync("/dev/stdin", "utf8"));