import std.stdio : readln, writeln, writefln;
import std.array : array, split;
import std.conv  : to;
import std.range.primitives;
import std.range : enumerate, iota, repeat, retro, assumeSorted;
import std.algorithm.searching  : all, any, canFind, count, countUntil;
import std.algorithm.comparison : max, min, clamp;
import std.algorithm.iteration  : each, group, filter, map, reduce, permutations, sum, uniq;
import std.algorithm.sorting    : sort;
import std.algorithm.mutation   : reverse, swap;


void main() {
    import std.algorithm : levenshteinDistance;

    string s,t;
    scan(s);
    scan(t);

    levenshteinDistance(s,t).writeln;
}




void scan(T...)(ref T args) {
    import std.stdio : readln;
    import std.array : split;
    import std.conv  : to;
    import std.range.primitives;

    string[] line = readln.split;
    foreach (ref arg; args) {
        arg = line.front.to!(typeof(arg));
        line.popFront();
    }
    assert(line.empty);
}



void fillAll(R, T)(ref R arr, T value) {
    static if (is(typeof(arr[] = value))) {
        arr[] = value;
    }
    else {
        foreach (ref e; arr) {
            fillAll(e, value);
        }
    }
}
