local mod = 1000000007
local function badd(x, y) return (x + y) % mod end
local tgtall = {
  "yukicoder",
  "?ukicoder",
  "y?kicoder",
  "yu?icoder",
  "yuk?coder",
  "yuki?oder",
  "yukic?der",
  "yukico?er",
  "yukicod?r",
  "yukicode?"
}
local ret = 0
local inf = 1000000007
local function solve(n, s, tgt)
  local t = {}
  for i = 1, 9 do
    t[i] = inf
  end
  for i = 1, n do
    for j = 1, 9 do
      if s:sub(i, i) == tgt:sub(j, j) then
        if j == 1 then
          t[j] = t[j] + 1
        else
          t[j] = badd(t[j], t[j - 1])
        end
      end
    end
  end
  ret = ret + t[9]
end

local n = io.read("*n", "*l")
local s = io.read()
for i = 1, #tgtall do
  solve(n, s, tgtall[i])
end
print(ret)