Forgotten measurements

input/code.cpp: In function 'int main()':
input/code.cpp:35:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   35 |     for (int i = 2; i < n.size(); i++) {
      |                     ~~^~~~~~~~~~
input/code.cpp:36:23: warning: 'f' may be used uninitialized in this function [-Wmaybe-uninitialized]
   36 |         if (n[i] == f || n[i] == s)

#include <bits/stdc++.h>
using namespace std;
#define endl "\n";

#define PRINT_ARR(arr, n) \
    do { \
        for (int i = 0; i < n; i++) { \
            cout << arr[i] << " "; \
        } \
        cout << endl; \
    } while (0)

typedef long long ll;

int main() {
    string n;
    cin >> n;
    char f;
    switch(n[0]) {
        case 'U':
            f='D';
            break;
        case 'D':
            f='U';
            break;
        case 'L':
            f='R';
            break;
        case 'R':
            f='L';
            break; 
    }
    char s=n[1];
    ll count = 1ll;
    for (int i = 2; i < n.size(); i++) {
        if (n[i] == f || n[i] == s)
            count++;
    }
    cout << count << endl;
    return 0;
}

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: ACCEPTED

Test 4

Verdict: WRONG ANSWER

Test 5

Verdict: ACCEPTED

Test 6

Verdict: WRONG ANSWER

Test 7

Verdict: ACCEPTED

Test 8

Verdict: ACCEPTED

Test 9

Verdict: WRONG ANSWER

Test 10

Verdict: ACCEPTED

Test 11

Verdict: WRONG ANSWER