#include <bits/stdc++.h>
#define For(i, a, b) for(int i = (a); i <= (b);i++)
#define Rof(i, a, b) for(int i = (a); i >= (b);i--)
using namespace std;

#define maxn 200005

int n, m, s;
struct node{
    int to, next;
}bian[maxn * 2];
int head[maxn];
int cnt = 1;

int dis[maxn];
int pre[maxn];
int tag[maxn];
int t = 0;

void add(int u, int v)
{
    cnt++;
    bian[cnt] = {v, head[u]};
    head[u] = cnt;
}
void pr(int u)
{
    printf("%d\n", dis[u] + 1);
    stack<int> st;
    while(u) st.push(u), u = pre[u];
    while(!st.empty()) printf("%d ", st.top()), st.pop();
    printf("\n");
}
bool dfs(int u, int fa)
{
    if(tag[u] == t) return 0;
    tag[u] = t;
    if(dis[u])  {
        printf("Possible\n");
        pr(u);
        pre[u] = fa, dis[u] = dis[fa] + 1;
        pr(u);
        return 1;
    }
    pre[u] = fa, dis[u] = dis[fa] + 1;
    for(int i = head[u];i;i = bian[i].next) {
        int v = bian[i].to;
        if(v == s) continue;
        if(dfs(v, u)) return 1;
    }
    return 0;
}
int main()
{
    scanf("%d%d%d", &n, &m, &s);
    For(i, 1, m) {
        int x, y;
        scanf("%d%d", &x, &y);
        add(x, y);
    }
    for(int i = head[s];i;i = bian[i].next) {
        int v = bian[i].to;
        t = v;
        if(dfs(v, s)) return 0;
    }
    printf("Impossible");
    return 0;
}
/*
5 5 1
1 2
2 3
1 4
4 3
3 5

5 5 1
1 2
2 3
3 4
2 5
5 4

3 3 2
1 2
2 3
3 1

10 16 1
1 2
1 3
1 4
1 5
1 6
1 7
1 8
1 9
1 10
2 3
2 4
2 5
2 6
2 7
2 8
2 9
2 10
*/