Forgotten measurements

input/code.cpp: In function 'int main()':
input/code.cpp:13:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   13 |     for (int i = 0; i < s.size(); ++i){
      |                     ~~^~~~~~~~~~

#include <vector>
#include <string>
#include <iostream>
#include <cmath>
 
using namespace std;
 
int main(){
    string s;
    int u = 0, l = 0 , d = 0, r = 0;

    cin >> s;
    for (int i = 0; i < s.size(); ++i){
        if (s[i] == 'U')
            ++u;
        if (s[i] == 'L')
            ++l;
        if (s[i] == 'D')
            ++d;
        if (s[i] == 'R')
            ++r;
    }
    cout << min(u, d) + min(r, l) << endl;
}

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: ACCEPTED

Test 4

Verdict: ACCEPTED

Test 5

Verdict: ACCEPTED

Test 6

Verdict: ACCEPTED

Test 7

Verdict: ACCEPTED

Test 8

Verdict: ACCEPTED

Test 9

Verdict: ACCEPTED

Test 10

Verdict: ACCEPTED

Test 11

Verdict: ACCEPTED