var input = require('fs').readFileSync('/dev/stdin', 'utf8');
var arr = input.trim().split(" ").map(Number);
var a = arr[0];
var b = arr[1];
var c = arr[2];
var d = arr[3];
if (a == b && c == d) console.log("yes");
else if (a == c && b == d) console.log("yes");
else if (a == d && b == c) console.log("yes");
else console.log("no");