process.stdin.resume();
        process.stdin.setEncoding('utf8');
        process.stdin.on('data', function (chunk) {
            main(chunk.trim());
        });

        function main(chunk) {
            var lines = chunk.split("\n");
            var n = Number(lines[0]);
            var blocks = lines[1].split(" ");
            var object = {};
            for (var i in blocks) {
                object[Number(blocks[i])] = Number(i);
            }
            var tmp = n;
            var i;
            for (i = n; i > 0; i--) {
                if (tmp == object[i]) {
                    tmp--;
                }
            }
            console.log(tmp);
        }