func countAndSay(n int) string {
if n==1{
return "1"
}
if n==2{
return "11"
}
last:=countAndSay(n-1)
tmp:=last[0]
index:=1
var ret string
for i:=1;i<len(last);i++{
if last[i]==tmp{
index++
continue
}else{
ret+=string(index+'0')
ret+=string(tmp)
index=1
tmp=last[i]
}
}
ret+=string(index+'0')
//a:=tmp-'0'
ret+=string(tmp)
return ret
}