function Main(input) {
    'use strict';
    let data = input.split("\n");
    let first_line = data[0].split("");
    let second_line = data[1];

    let num_list = new Array();
    for (let x of first_line) {
        num_list.push(parseInt(x));
    }

    let max = Math.max(...num_list);
    let min = Math.min(...num_list);
    console.log(max-min);
}

// Don't edit this line!
Main(require("fs").readFileSync("/dev/stdin", "utf8"));