import std.stdio,
       std.conv,
       std.string,
       std.range,
       std.math,
       std.algorithm;

void main()
{
    auto N = readln.strip.to!int;
    auto M = readln.strip.to!int;
    int[] P, Q;
    foreach (_; 0 .. M)
    {
        auto input = readln.split.to!(int[]);
        P ~= input[0];
        Q ~= input[1];
    }

    auto cup = [0, 1, 2, 3];
    iota(M).each!(i=>swap(cup[P[i]],cup[Q[i]]));
    cup.countUntil(N).writeln;
}