#include <stdio.h>
#include <stdlib.h>
#include <string.h>

int solution(char* s) {
    int n = strlen(s);
    if (n % 4 != 0) return 0;
    
    int target = n / 4;
    int count[4] = {0}; // Q, W, E, R
    
    // Count frequency of each character
    for (int i = 0; i < n; i++) {
        if (s[i] == 'Q') count[0]++;
        else if (s[i] == 'W') count[1]++;
        else if (s[i] == 'E') count[2]++;
        else if (s[i] == 'R') count[3]++;
    }
    
    // Find excess characters (more than target)
    int excess[4] = {0};
    int totalExcess = 0;
    for (int i = 0; i < 4; i++) {
        if (count[i] > target) {
            excess[i] = count[i] - target;
            totalExcess += excess[i];
        }
    }
    
    // If no excess, already balanced
    if (totalExcess == 0) return 0;
    
    // Use sliding window to find minimum substring containing all excess
    int left = 0;
    int windowCount[4] = {0};
    int minLen = n;
    
    for (int right = 0; right < n; right++) {
        // Expand window
        int idx = (s[right] == 'Q') ? 0 : (s[right] == 'W') ? 1 : (s[right] == 'E') ? 2 : 3;
        windowCount[idx]++;
        
        // Try to shrink window
        while (left <= right) {
            // Check if current window contains enough excess characters
            int valid = 1;
            for (int i = 0; i < 4; i++) {
                if (excess[i] > 0 && windowCount[i] < excess[i]) {
                    valid = 0;
                    break;
                }
            }
            
            if (valid) {
                int currentLen = right - left + 1;
                if (currentLen < minLen) {
                    minLen = currentLen;
                }
                int leftIdx = (s[left] == 'Q') ? 0 : (s[left] == 'W') ? 1 : (s[left] == 'E') ? 2 : 3;
                windowCount[leftIdx]--;
                left++;
            } else {
                break;
            }
        }
    }
    
    return minLen;
}

int main() {
    char s[100005];
    fgets(s, sizeof(s), stdin);
    s[strcspn(s, "\n")] = 0;
    printf("%d\n", solution(s));
    return 0;
}