#include <iostream>
#include <vector>

using namespace std;

int sub_vector(vector<int> source, vector<int> sub) {
    if (sub.size() > source.size()) return -1;
    for (int i = 0; i < source.size() - sub.size() + 1; ++i) {
        bool found = true;
        for (int j = 0; j < sub.size(); ++j) {
            if (sub[j] != source[i + j]) {
                found = false;
                break;
            }
        }
        if (found) {
            return i;
        }
    }
    return -1;
}

int main() {
    vector<int> source = {1,2,3,4,5};
    vector<int> sub = {1,2,3,4,5};

    cout << sub_vector(source, sub) << endl;
}