package main

import (
	"fmt"
	"strings"
)

func main() {
	s := "Hi He Lied Because Boron Could Not Oxidize Fluorine. New Nations Might Also Sign Peace Security Clause. Arthur King Can."
	firstOnly := make(map[int]struct{})
	for _, i := range []int{1, 5, 6, 7, 8, 9, 15, 16, 19} {
		firstOnly[i] = struct{}{}
	}
	result := make(map[string]int)
	for i, w := range strings.Split(s, " ") {
		var n int
		if _, ok := firstOnly[i+1]; ok {
			n = 1
		} else {
			n = 2
		}
		result[w[:n]] = i + 1
	}
	fmt.Println(result)
}