Forgotten measurements

input/code.cpp: In function 'int main()':
input/code.cpp:12:14: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   12 |     while (i < input.size()) {
      |            ~~^~~~~~~~~~~~~~

#include <bits/stdc++.h>

using namespace std;
typedef long long ll;
typedef uint64_t u64;

int main() {
    string input;
    cin >> input;
    int out = 1;
    int i = 0;
    while (i < input.size()) {
        if (input[i] == 'U' && input[i+2]=='D') {
            out++;
            input.erase(i, 3);
        }
        if (input[i] == 'D' && input[i+2]=='U') {
            out++;
            input.erase(i, 3);
        }
        if (input[i] == 'L' && input[i+2]=='R') {
            out++;
            input.erase(i, 3);
        }
        if (input[i] == 'R' && input[i+2]=='L') {
            out++;
            input.erase(i, 3);
        }
        i++;
    }
    cout << out;
}

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: WRONG ANSWER

Test 4

Verdict: WRONG ANSWER

Test 5

Verdict: WRONG ANSWER

Test 6

Verdict: TIME LIMIT EXCEEDED

Test 7

Verdict: TIME LIMIT EXCEEDED

Test 8

Verdict: TIME LIMIT EXCEEDED

Test 9

Verdict: TIME LIMIT EXCEEDED

Test 10

Verdict: TIME LIMIT EXCEEDED

Test 11

Verdict: TIME LIMIT EXCEEDED