A - ?UPC
Source: atcoder
Difficulty: 100

Problem Statement
You are given a string
S
. Here, the first character of
S
is an uppercase English letter, and the second and subsequent characters are lowercase English letters.
Print the string formed by concatenating the first character of
S
and
UPC
in this order.
Constraints
S
is a string of length between
1
and
100
, inclusive.
The first character of
S
is an uppercase English letter.
The second and subsequent characters of
S
are lowercase English letters.
Input
The input is given from Standard Input in the following format:
S
Output
Print the string formed by concatenating the first character of
S
and
UPC
in this order.
Sample Input 1
Kyoto
Sample Output 1
KUPC
The first character of
Kyoto
is
K
, so concatenate
K
and
UPC
, and print
KUPC
.
Sample Input 2
Tohoku
Sample Output 2
TUPC

C++ solution:
#include <bits/stdc++.h>

using namespace std;

using ii = pair<int,int>;
using vii = vector<ii>  ;
using vi = vector<int>  ;
#define ln  '\n'
#define ll long long
#define pb push_back
#define fi first
#define se second
#define sz(v) ((int)(v).size())
#define all(v) (v).begin(),(v).end()
#define rall(v) (v).rbegin(),(v).rend()
#define f(i, a, b)  for(ll i = (ll)a; i < (ll)b; i++)
#define fer(i, b, a)  for(ll i = (ll)a - 1; i >= (ll)b; i--)

void so(int test){
        string s;
        cin >> s;
        string ret = "UPC";
        cout << s[0] + ret;
}

int main() {
	ios::sync_with_stdio(false);
	cin.tie(0);

	int tt = 1;
	int test = 1;
	while (tt--){
		so(test++);
	}
	return 0;
}

Go solution:
package main

import (
    "bufio"
    "fmt"
    "os"
)

var sc = bufio.NewScanner(os.Stdin)

func nextStr() string {
    sc.Scan()
    return sc.Text()
}

func main() {
    sc.Split(bufio.ScanWords)

    s := nextStr()
    fmt.Print(s[:1]+"UPC")
}

Java solution:
import java.io.*;

// 処理
class Process {
    private String S;

    Process(String S) {
        this.S = S;
    }

    String getResult() {
        return (S.charAt(0) + "UPC");
    }
}

public class Main {
    public static void main(String[] args) throws IOException {
        var bufferedReader = new BufferedReader(new InputStreamReader(System.in));
        var printWriter    = new PrintWriter(new BufferedWriter(new OutputStreamWriter(System.out)));

        // 入力
        String S = bufferedReader.readLine().trim();

        // 出力
        printWriter.println((new Process(S)).getResult());

        bufferedReader.close();
        printWriter.close();
    }
}

JavaScript solution:
let joinUPC = (input) => {
  console.log(input.charAt(0)+'UPC');
}
joinUPC(require("fs").readFileSync("/dev/stdin", "utf8"));

Python solution:
S = input()

print(S[0]+"UPC")

Ruby solution:
S = gets.chomp

puts S[0] + "UPC"