var x = Int(readLine()!)!
var pr = [Int](), n = -1
for i in 2...200000{
    while x % i == 0{
        x /= i
        pr.append(i)
    }
}
if x == 1{
    if pr.count == 0{
        pr.append(1)
    }
    let s = pr.reduce(0,+)
    if s <= 200000{
        n = s+pr.count
    }
}
let k = pr.count

print(n)
if n != -1{
    if n > 2{
    for i in 1..<k{
        print("\(i) \(i+1)")
    }
    }
    var l = k+1
    for i in 1...k{
        for j in l..<l+pr[i-1]{
            print("\(i) \(j)")
        }
        l = l + pr[i-1]
    }
    let c = [String](repeating:"b",count:k) + [String](repeating:"g",count:n-k)
    let nc = c.joined(separator:" ")
    print(nc)
}