M = [rand(1:20) for i in 1:5, j in 1:10]
R, C = size(M)
println("The full matrix is:")
println(M, "\n")
println("Find the first 20:")
for i in 1:R, j in 1:C
n = M[i,j]
@printf "%4d" n
if n == 20
println()
break
elseif j == C
end