#include <iostream>
#include <sstream>
#include <vector>
using namespace std;
int main() {
string s, tmp;
getline(cin, s);
stringstream ss(s);
vector<string> vec;
while (ss >> tmp) {
vec.push_back(tmp);
}
int n = vec.size();
for (char x: vec[n - 1]) cout << (char)tolower(x);
for (int i = 0; i < n - 1; ++i) {
cout << (char)tolower(vec[i][0]);
}
cout << "@stu.ptit.edu.vn";
return 0;
}
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