#include <iostream>
#include <cstdio>
using namespace std;
#define rep(i,n) for(int i=0;i<(n);i++)

int n, k;
int x[1010], y[1010];
int goal[110];//goal[i] := i番目から出発すると、何番目にたどり着くか
int main(void){
	cin >> n >> k;
	rep(i, k) cin >> x[i] >> y[i];

	for (int i = 1; i <= n; ++i){
		goal[i] = i;
	}

	for (int i = k - 1; i >= 0; --i){
		swap(goal[x[i]], goal[y[i]]);
	}

	int now = 1, ans = 0;;
	while(1){
		now = goal[now];
		ans++;
		if(now == 1){
			printf("%d\n", ans);
			return 0;
		}
	}
}