13. Prime Pairs

package main

import (
    "fmt"
    "math"
)

func main() {
    var firstStart, secondStart, firstDiff, secondDiff int
    fmt.Scanln(&firstStart)
    fmt.Scanln(&secondStart)
    fmt.Scanln(&firstDiff)
    fmt.Scanln(&secondDiff)

    for i := firstStart; i <= firstStart + firstDiff; i++ {
        for j := secondStart; j <= secondStart + secondDiff; j++ {
            var isFirstPrime = true
            var isSecondPrime = true
            for k := 2; k <= int(math.Sqrt(float64(i))); k++ {
                if i % k == 0 {
                    isFirstPrime = false
                    break
                }
            }
            for k := 2; k <= int(math.Sqrt(float64(j))); k++ {
                if j % k == 0 {
                    isSecondPrime = false
                    break
                }
            }
            if isFirstPrime && isSecondPrime {
                fmt.Printf("%d%d\n", i, j)
            }
        }
    }
}