using namespace std;
#include <cmath>
#include <iostream>
#include <vector>
#include <algorithm>
#include <string>
#include <set>
#include <map>
#include <list>
#include <time.h>
#include <math.h>
#include <random>
#include <deque>
#include <queue>
#include <cassert>
#include <unordered_map>
#include <unordered_set>
#include <iomanip>
#include <bitset>
#include <sstream>
#include <chrono>
#include <stack>

typedef long long ll;


bool check(string s) {
for (int i = 0; i < s.size() / 2; ++i) {
    if (s[i] != s[(int)s.size() - i - 1]) {
        return false;
    }
    return true;
}
}
int main() {
    ios::sync_with_stdio(false);
    string s;
    cin >> s;
    int n = s.size();
    int r = n / 2;
    string p = "";
    for (int i = 0; i < n - 1; ++i) {
        p += s[i];
        string cur = "";
        for (int j = i + 1; j < n; ++j) {
            cur += s[j];
        }
        cur += p;
        if (check(cur)) {
            cout << 1;
            return 0;
        }
    }
    set<char> have;
    for (int i = 0; i < n / 2; ++i) {
        have.insert(s[i]);
    }
    if (have.size() == 1) {
        cout << "Impossible";
        return 0;
    }
    cout << 2;
}