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

int solution(int* nums, int n) {
    int minValue = INT_MAX;
    
    // Try all possible partitions
    for (int mask = 1; mask < (1 << n) - 1; mask++) {
        int nums1[1000], nums2[1000];
        int len1 = 0, len2 = 0;
        
        for (int i = 0; i < n; i++) {
            if (mask & (1 << i)) {
                nums1[len1++] = nums[i];
            } else {
                nums2[len2++] = nums[i];
            }
        }
        
        if (len1 > 0 && len2 > 0) {
            int maxNums1 = nums1[0];
            for (int i = 1; i < len1; i++) {
                if (nums1[i] > maxNums1) maxNums1 = nums1[i];
            }
            
            int minNums2 = nums2[0];
            for (int i = 1; i < len2; i++) {
                if (nums2[i] < minNums2) minNums2 = nums2[i];
            }
            
            int value = abs(maxNums1 - minNums2);
            if (value < minValue) minValue = value;
        }
    }
    
    return minValue;
}

int main() {
    char line[10000];
    fgets(line, sizeof(line), stdin);
    
    // Parse array manually
    int nums[1000];
    int n = 0;
    char* ptr = strchr(line, '[') + 1;
    char* token = strtok(ptr, ",]");
    while (token != NULL) {
        nums[n++] = atoi(token);
        token = strtok(NULL, ",]");
    }
    
    printf("%d\n", solution(nums, n));
    return 0;
}