package main

import (
	"fmt"

	"internal/util"
)

func main() {
	ids := util.ReadInput()

	for _, box1 := range ids {
		for _, box2 := range ids {
			diffIndex := -1 // diffIndex doubles as the letter to remove and a 'found' flag
			for i := range box1 {
				if box1[i] != box2[i] {
					if diffIndex != -1 {
						// If we reach here, we've detected more than one error, so we set
						// diffIndex back to -1 here to avoid the conditional below this loop.
						diffIndex = -1
						break
					}
					diffIndex = i
				}
			}
			if diffIndex != -1 {
				fmt.Printf("%s%s\n", box1[0:diffIndex], box1[diffIndex+1:])
				return
			}
		}
	}
}