#include <bits/stdc++.h>
using namespace std;
using ll=long long;
using ull=unsigned long long;
using P=pair<ll,ll>;
template<typename T>using minque=priority_queue<T,vector<T>,greater<T>>;
template<typename T>bool chmax(T &a,const T &b){return (a<b?(a=b,true):false);}
template<typename T>bool chmin(T &a,const T &b){return (a>b?(a=b,true):false);}
template<typename T1,typename T2>istream &operator>>(istream &is,pair<T1,T2>&p){is>>p.first>>p.second;return is;}
template<typename T1,typename T2,typename T3>istream &operator>>(istream &is,tuple<T1,T2,T3>&a){is>>std::get<0>(a)>>std::get<1>(a)>>std::get<2>(a);return is;}
template<typename T,size_t n>istream &operator>>(istream &is,array<T,n>&a){for(auto&i:a)is>>i;return is;}
template<typename T>istream &operator>>(istream &is,vector<T> &a){for(auto &i:a)is>>i;return is;}
template<typename T1,typename T2>void operator++(pair<T1,T2>&a,int n){a.first++,a.second++;}
template<typename T1,typename T2>void operator--(pair<T1,T2>&a,int n){a.first--,a.second--;}
template<typename T>void operator++(vector<T>&a,int n){for(auto &i:a)i++;}
template<typename T>void operator--(vector<T>&a,int n){for(auto &i:a)i--;}
#define overload3(_1,_2,_3,name,...) name
#define rep1(i,n) for(int i=0;i<(int)(n);i++)
#define rep2(i,l,r) for(int i=(int)(l);i<(int)(r);i++)
#define rep(...) overload3(__VA_ARGS__,rep2,rep1)(__VA_ARGS__)
#define reps(i,l,r) rep2(i,l,r)
#define all(x) x.begin(),x.end()
#define pcnt(x) __builtin_popcountll(x)
#define fin(x) return cout<<(x)<<'\n',static_cast<void>(0)
#define yn(x) cout<<((x)?"Yes\n":"No\n")
#define uniq(x) sort(all(x)),x.erase(unique(all(x)),x.end())
template<typename T>
inline int fkey(vector<T>&z,T key){return lower_bound(z.begin(),z.end(),key)-z.begin();}
ll myceil(ll a,ll b){return (a+b-1)/b;}
template<typename T,size_t n,size_t id=0>
auto vec(const int (&d)[n],const T &init=T()){
  if constexpr (id<n)return vector(d[id],vec<T,n,id+1>(d,init));
  else return init;
}
#ifdef LOCAL
#include<debug.h>
#define SWITCH(a,b) (a)
#else
#define debug(...) static_cast<void>(0)
#define debugg(...) static_cast<void>(0)
#define SWITCH(a,b) (b)
template<typename T1,typename T2>ostream &operator<<(ostream &os,const pair<T1,T2>&p){os<<p.first<<' '<<p.second;return os;}
#endif
struct Timer{
  clock_t start;
  Timer(){
    start=clock();
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    cout<<fixed<<setprecision(16);
  }
  inline double now(){return (double)(clock()-start)/1000;}
  #ifdef LOCAL
  ~Timer(){
    cerr<<"time:";
    cerr<<now();
    cerr<<"ms\n";
  }
  #endif
}timer;
void SOLVE();
int main(){
  int testcase=1;
  //cin>>testcase;
  for(int i=0;i<testcase;i++){
    SOLVE();
  }
}
#include<type_traits>
#include<concepts>
template<typename T>
constexpr std::enable_if_t<std::numeric_limits<T>::digits<=32,int>msb(T n){return n==0?-1:31-__builtin_clz(n);}
template<typename T>
constexpr std::enable_if_t<(std::numeric_limits<T>::digits>32),int>msb(T n){return n==0?-1:63-__builtin_clzll(n);}

template<typename T>
constexpr std::enable_if_t<std::numeric_limits<T>::digits<=32,int>lsb(T n){return n==0?-1:__builtin_ctz(n);}
template<typename T>
constexpr std::enable_if_t<(std::numeric_limits<T>::digits>32),int>lsb(T n){return n==0?-1:__builtin_ctzll(n);}

template<typename T>
constexpr std::enable_if_t<std::is_integral_v<T>,T>floor_pow2(T n){return n==0?0:T(1)<<msb(n);}

template<typename T>
constexpr std::enable_if_t<std::is_integral_v<T>,T>ceil_pow2(T n){return n<=1?1:T(1)<<(msb(n-1)+1);}

template<std::integral T>
constexpr T safe_div(T a,T b){return a/b-(a%b&&(a^b)<0);}
template<std::integral T>
constexpr T safe_ceil(T a,T b){return a/b+(a%b&&(a^b)>0);}
template<typename M,int L=5>
struct SparseTable{
  using S=typename M::S;
private:
  std::vector<S>dat,prefix,suffix;
  std::vector<std::vector<S>>sp;
public:
  SparseTable(){}
  SparseTable(std::vector<S>a):dat(a){
    int n=a.size();
    n=(n+(1<<L)-1)&~((1<<L)-1);
    a.resize(n,M::e());
    prefix=suffix=a;
    std::vector<S>d2(n>>L,M::e());
    for(int i=0;i<d2.size();i++){
      for(int j=0;j<(1<<L);j++)d2[i]=M::op(d2[i],a[(i<<L)+j]);
    }
    for(int i=0;i<(n>>L);i++){
      for(int j=1;j<(1<<L);j++)prefix[(i<<L)+j]=M::op(prefix[(i<<L)+j-1],prefix[(i<<L)+j]);
    }
    for(int i=(n>>L)-1;i>=0;i--){
      for(int j=(1<<L)-1;j>=1;j--)suffix[(i<<L)+j-1]=M::op(suffix[(i<<L)+j-1],suffix[(i<<L)+j]);
    }
    int d=(d2.size()==1?1:32-__builtin_clz(d2.size()-1));
    sp.resize(d,d2);
    for(int i=1;i<d;i++){
      int w=1<<i;
      for(int j=w;j<=d2.size();j+=w*2){
        for(int k=j-2;k>=j-w;k--)sp[i][k]=M::op(d2[k],sp[i][k+1]);
        int r=std::min<int>(d2.size(),j+w);
        for(int k=j+1;k<r;k++)sp[i][k]=M::op(sp[i][k-1],d2[k]);
      }
    }
  }
  S prod(int l,int r)const{
    if(l==r)return M::e();
    r--;
    int lid=l>>L,rid=r>>L;
    if(lid==rid){
      S ret=M::e();
      for(int i=l;i<=r;i++)ret=M::op(ret,dat[i]);
      return ret;
    }
    else{
      lid++;
      rid--;
      S mid=M::e();
      if(lid==rid)mid=sp[0][lid];
      else if(lid<rid){
        int s=msb(lid^rid);
        mid=M::op(sp[s][lid],sp[s][rid]);
      }
      return M::op(suffix[l],M::op(mid,prefix[r]));
    }
  }
};
template<typename T,int N,int M=N>
struct ConstantMatrix{
private:
  std::array<std::array<T,M>,N>dat;
public:
  ConstantMatrix(){
    dat.fill([](){std::array<T,M>res;res.fill(T());return res;}());
  }
  static ConstantMatrix E(){
    static_assert(N==M);
    ConstantMatrix res;
    for(int i=0;i<N;i++)res[i][i]=T(1);
    return res;
  }
  inline  ConstantMatrix &operator+=(const ConstantMatrix&rhs){
    for(int i=0;i<N;i++)for(int j=0;j<M;j++)(*this)[i][j]+=rhs[i][j];
    return *this;
  }
  inline ConstantMatrix &operator-=(const ConstantMatrix&rhs){
    for(int i=0;i<N;i++)for(int j=0;j<M;j++)(*this)[i][j]-=rhs[i][j];
    return *this;
  }
  inline ConstantMatrix &operator*=(const ConstantMatrix&rhs){
    static_assert(N==M);
    ConstantMatrix res;
    for(int i=0;i<N;i++)for(int j=0;j<M;j++)for(int k=0;k<M;k++)res[i][k]+=(*this)[i][j]*rhs[j][k];
    (*this)=std::move(res);
    return *this;
  }
  friend ConstantMatrix operator+(const ConstantMatrix&lhs,const ConstantMatrix&rhs){return ConstantMatrix(lhs)+=rhs;}
  friend ConstantMatrix operator-(const ConstantMatrix&lhs,const ConstantMatrix&rhs){return ConstantMatrix(lhs)-=rhs;}
  template<int K>friend ConstantMatrix<T,N,K> operator*(const ConstantMatrix&lhs,const ConstantMatrix<T,M,K>&rhs){
    ConstantMatrix<T,N,K>res;
    for(int i=0;i<N;i++)for(int j=0;j<M;j++)for(int k=0;k<K;k++)res[i][k]+=lhs[i][j]*rhs[j][k];
    return res;
  }
  std::array<T,M> &operator[](int i){return dat[i];}
  const std::array<T,M> &operator[](int i)const{return dat[i];}
  friend bool operator==(const ConstantMatrix&lhs,const ConstantMatrix&rhs){
    for(int i=0;i<N;i++)for(int j=0;j<M;j++)if(lhs[i][j]!=rhs[i][j])return false;
    return true;
  }
  friend bool operator!=(const ConstantMatrix&lhs,const ConstantMatrix&rhs){
    for(int i=0;i<N;i++)for(int j=0;j<M;j++)if(lhs[i][j]!=rhs[i][j])return true;
    return false;
  }
  T det()const{
    static_assert(N==M);
    T res=1;
    ConstantMatrix mat(*this);
    for(int i=0;i<M;i++){
      int idx=-1;
      for(int j=i;j<N;j++)if(mat[j][i]!=T()){
        idx=j;
        break;
      }
      if(idx==-1)return T();
      if(i!=idx)std::swap(mat[i],mat[idx]),res=-res;
      res*=mat[i][i];
      T inv_ii=mat[i][i].inv();
      for(int j=i+1;j<M;j++)mat[i][j]*=inv_ii;
      for(int j=i+1;j<N;j++){
        T coef=-mat[j][i];
        for(int k=i+1;k<M;k++)mat[j][k]+=coef*mat[i][k];
      }
    }
    return res;
  }
  ConstantMatrix inv()const{
    static_assert(N==M);
    ConstantMatrix res=E(),mat=(*this);
    for(int i=0;i<N;i++){
      int id=-1;
      for(int j=i;j<N;j++)if(mat[j][i]!=T()){
        id=j;
        break;
      }
      if(id==-1)return ConstantMatrix();
      if(i!=id){
        std::swap(mat[i],mat[id]);
        std::swap(res[i],res[id]);
      }
      T inv=mat[i][i].inv();
      for(int j=0;j<N;j++)if(i!=j){
        T x=mat[j][i];
        for(int k=0;k<N;k++){
          mat[j][k]-=mat[i][k]*x;
          res[j][k]-=res[i][k]*x;
        }
      }
    }
    return res;
  }
  template<std::integral U>
  ConstantMatrix pow(U k)const{
    static_assert(N==M);
    ConstantMatrix res=ConstantMatrix::E(),a(*this);
    while(k){
      if(k&1)res*=a;
      a*=a;
      k>>=1;
    }
    return res;
  }
  std::vector<std::vector<T>>to_vector()const{
    std::vector<std::vector<T>>res(N,std::vector<T>(M));
    for(int i=0;i<N;i++)for(int j=0;j<M;j++)res[i][j]=dat[i][j];
    return res;
  }
  friend std::ostream &operator<<(std::ostream &os,const ConstantMatrix&rhs){
    for(int i=0;i<N;i++){
      for(int j=0;j<M;j++)os<<rhs[i][j]<<" \n"[j+1==M];
    }
    return os;
  }
};
int operate(int lhs,int rhs,int op){
  if(op==0)return lhs|rhs;
  else if(op==1)return lhs&rhs;
  else if(op==2)return lhs^rhs;
  else{
    debug(lhs,rhs,op);
  }
  return -1;
}
struct M{
  struct S{
    // ll cntl[2]={0,0};
    ConstantMatrix<ll,2,2>mat,allmat;
    ll cntr[2]={0,0};
    // ll al=0;
    ll ans=0;
    int rop=-1;
  };
  static S op(S x,S y){
    if(x.rop==-1)return y;
    if(y.rop==-1)return x;
    S res;
    res.rop=y.rop;
    res.mat=x.mat+y.mat*x.allmat;
    res.allmat=y.allmat*x.allmat;
    rep(i,2){
      res.cntr[i]+=y.cntr[i];
    }
    // res.cntl[operate(x.al,0,x.rop)]+=y.cntl[0];
    // res.cntl[operate(x.al,1,x.rop)]+=y.cntl[1];
    // debug(res.cntr[0]);
    // debug(y.allmat);
    debug(y.allmat);
    rep(i,2)rep(j,2)if(y.allmat[j][i])res.cntr[j]+=x.cntr[i];
    // res.cntr[operate(0,y.al,x.rop)]+=x.cntr[0];
    // res.cntr[operate(1,y.al,x.rop)]+=x.cntr[1];
    // res.al=operate(x.al,y.al,x.rop);
    res.ans=x.ans+y.ans;
    // debug(res.cntr[0]);
    // debug(x.ans,y.ans,res.ans);
    rep(i,2){
      res.ans+=x.cntr[i]*y.mat[1][i];
      // if(y.allmat[1][i])res.ans+=x.cntr[i];
      // debug(i,res.ans,x.cntr[i]);
    }
    // rep(i,2)rep(j,2){
    //   if(operate(i,j,x.rop))res.ans+=(ll)x.cntr[i]*y.cntl[j];
    // }
    return res;
  }
  static S e(){return S();}
};
ConstantMatrix<ll,2,2>getmat(char c,int v){
  ConstantMatrix<ll,2,2>res;
  if(c=='+'){
    if(v==0)res[0][0]=res[1][1]=1;
    else res[1][0]=res[1][1]=1;
  }
  else if(c=='*'){
    if(v==1)res[0][0]=res[1][1]=1;
    else res[0][0]=res[0][1]=1;
  }
  else{
    if(v==0)res[0][0]=res[1][1]=1;
    else res[0][1]=res[1][0]=1;
  }
  return res;
}
void SOLVE(){
  int n,q;
  cin>>n>>q;
  n=(n+1)/2;
  string x;
  cin>>x;
  // x+='+';
  vector<M::S>init(n);
  rep(i,n){
    // init[i].cntl[x[i*2]=='T']++;
    init[i].cntr[x[i*2]=='T']++;
    // init[i].al=x[i*2]=='T';
    if(x[i*2]=='T')init[i].ans++;
    init[i].rop=0;
    init[i].mat=init[i].allmat=getmat(i==0?'+':x[i*2-1],x[i*2]=='T');
    init[i].allmat=init[i].mat;
    // debug(i,init[i]);
    debug(i,init[i].cntr[0]);
  }
  SparseTable<M>sp(init);
  debug('U');
  rep(i,q){
    int l,r;
    cin>>l>>r;
    l--,r--;
    l/=2,r/=2;
    cout<<sp.prod(l,r+1).ans<<'\n';
  }
}