#include

using namespace std;
char c;
int main()
{
    cin >> c;
    cout << (char)(c+31);
    return 0;
}

$$#khanhtaon$$

#include
using namespace std;

int main() {
    // Declare variables
    char ch, precedingLetter;

    // Input an uppercase letter
    cout << "Enter an uppercase letter: ";
    cin >> ch;

    // Convert the uppercase letter to lowercase and find the preceding letter
    precedingLetter = ch - 1;

    // Print the result
    cout << "The preceding letter is: " << precedingLetter << endl;

    return 0;
}