[baekjoon-1463] 1λ‘ λ§λ€κΈ° μ νμ dp[1] = 0 dp[n] = Math.min(dp[n-1], dp[n/2], dp[n/3]) + 1 // n/2, n/3μ λλμ΄ λ¨μ΄μ§λμ§ νμΈ