#include<bits/stdc++.h>
#define ALL(v) std::begin(v),std::end(v)
using lint=long long;
using ld=long double;
void cmn(lint&x,lint y){if(x>y)x=y;}
int main(){
    std::cin.tie(nullptr);std::ios_base::sync_with_stdio(false);
    std::cout.setf(std::ios_base::fixed);std::cout.precision(15);
    lint n;std::cin>>n;
    std::vector<std::string>s(n);
    for(auto&&t:s)std::cin>>t;
    std::vector<std::vector<lint>>a(n);
    for(lint i=n-1;i>=0;i--){
        auto&&now=a.at(i);
        a.at(i).resize(s.at(i).length(),1);
        if(i==n-1)continue;
        auto&next=a.at(i+1);
        for(lint j=0;j<(lint)std::min(now.size(),next.size());j++){
            if(s.at(i).at(j)!=s.at(i+1).at(j))continue;
            now.at(j)=next.at(j)+1;
            if(j)cmn(now.at(j),now.at(j-1));
        }
    }
    auto comb=[&](lint n){return n*(n+1)*(n+2)/6;};
    lint ans=0;
    for(lint i=0;i<n;i++){
        for(lint j=0;j<(lint)a.at(i).size();j++){
            if(i&&j<(lint)a.at(i-1).size()&&1<a.at(i-1).at(j))continue;
            ans+=comb(a.at(i).at(j));
        }
    }
    std::cout<<ans<<'\n';
}