package main

import (
	"fmt"
	"io"
	"os"
)

type validator struct {
	Numbers []int
}

func newValidator() *validator {
	return &validator{
		Numbers: []int{},
	}
}

func (v *validator) validate(number int) (ok bool) {
	for i1, num1 := range v.Numbers {
		for i2, num2 := range v.Numbers {
			if i1 == i2 {
				continue
			}
			if num1+num2 == number {
				ok = true
				return
			}
		}
	}
	return
}

func (v *validator) Feed(number int) (ok bool) {
	if len(v.Numbers) >= 25 {
		// check if valid number
		if !v.validate(number) {
			return
		}
		v.Numbers = append(v.Numbers[len(v.Numbers)-24:], number)
	} else {
		v.Numbers = append(v.Numbers, number)
	}
	ok = true
	return
}

func main() {
	f, err := os.Open("input")
	if err != nil {
		panic(err)
	}

	v := newValidator()

	number := 0

	for {
		_, err := fmt.Fscanf(f, "%d\n", &number)
		if err == io.EOF {
			break
		}
		if err != nil {
			panic(err)
		}

		if !v.Feed(number) {
			fmt.Printf("%d does not validate\n", number)
			break
		}
	}

}