function main() {
    console.log(solve(load()));
}

function toInt(num) {
    return parseInt(num);
}

function load() {
    const {readFileSync} = require('fs');
    return readFileSync('./input', 'utf8');
}

function solve(input) {
    const n = Number(input.split('\n')[0]);
    const block_list = input.split('\n')[1].split(' ').map(toInt);

    let search_number = n;
    let sorted_count = 0;

    for (let i = block_list.length - 1;0 <= i;i--) {
        if (block_list[i] === search_number) {
            search_number--;
            sorted_count++;
        }
    }

    return n - sorted_count;
}

main();