local read = setmetatable({}, {__index = function(t, k) local a = {} for i=1,#k do table.insert(a, '*'..string.sub(k, i, i)) end local r = io.read local u = table.unpack or unpack return function() return r(u(a)) end end})
read.N = function(N) local t={} for i=1,N do t[i]=read.n() end return t end
string.totable = function(s) local t={} local u=string.sub for i=1,#s do t[i] = u(s, i, i) end return t end
string.split = function(s) local t={} for w in string.gmatch(s, "[^%s]+") do table.insert(t, w) end return (table.unpack or unpack)(t) end
local function array(dimension, default_val) local n=dimension local m={}if default_val~=nil then m[1]={__index=function()return default_val end}end for i=2,n do m[i]={__index=function(p, k)local c=setmetatable({},m[i-1])rawset(p,k,c)return c end}end return setmetatable({},m[n])end
----

---
local MOD = math.floor(10^9) + 7
local L = read.l():totable()
local N = #L
local tbl = array(2, 0)
local FIT = 0
local SMALLER = 1
tbl[0][FIT] = 1

for i=1,N do
    -- decide tbl[i] from tbl[i-1]
    local ld = tonumber(L[i])
    local oldtbl = tbl[i-1]
    local newtbl = tbl[i]
    local function has_transition(na, nb, oldfs, newfs)
        if na == 0 and nb == 0 then
        elseif na == 0 and nb == 1 then
        elseif na == 1 and nb == 0 then
        elseif na == 1 and nb == 1 then
            return false
        end
        local constraint_digit = ld
        local new_digit = na + nb
        if oldfs == FIT and newfs == FIT then
            return new_digit == constraint_digit
        elseif oldfs == FIT and newfs == SMALLER then
            return new_digit < constraint_digit
        elseif oldfs == SMALLER and newfs == FIT then
            return false
        elseif oldfs == SMALLER and newfs == SMALLER then
            return true
        end
    end
    local function do_transition(newfs, oldfs)
        local v = oldtbl[oldfs]
        newtbl[newfs] = (newtbl[newfs] + v) % MOD
    end
    for na=0,1 do
        for nb=0,1 do
            for oldfs=0,1 do
                for newfs=0,1 do
                    if has_transition(na, nb, oldfs, newfs) then
                        do_transition(newfs, oldfs)
                    end
                end
            end
        end
    end
end
local ans = (tbl[N][FIT] + tbl[N][SMALLER]) % MOD
print(ans)