import std;

void main () {
    string H, S;
    readln.read(H, S);

    if (abs((H[$-1]-'0') - (S[$-1]-'0')) % 2 == 0) {
        writeln("Possible");
    } else {
        writeln("Impossible");
    }
}

void read(T...)(string S, ref T args) {
    auto buf = S.split;
    foreach (i, ref arg; args) {
        arg = buf[i].to!(typeof(arg));
    }
}