local n, q = io.read("*n", "*n", "*l")
local s = io.read()
local t = {}
for i = 1, 26 do
  t[i] = {0}
end
for i = 1, n do
  local b = s:byte(i) - 96
  for j = 1, 26 do
    if b == j then
      t[j][i + 1] = t[j][i] + 1
    else
      t[j][i + 1] = t[j][i]
    end
  end
end
for iq = 1, q do
  local l, r, x = io.read("*n", "*n", "*n")
  for i = 1, 26 do
    local z = t[i][r + 1] - t[i][l]
    if x <= z then print(string.char(96 + i)) break end
    x = x - z
  end
end