#pragma GCC optimize ("O3")

#include <iostream>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include <map>
#include <unordered_map>
#include <set>
#include <unordered_set>
#include <queue>
#include <set>
#include <algorithm>
#include <numeric>
#include <list>
using namespace std;

using QWORD  = uint64_t;
using SQWORD = int64_t;
using DWORD  = uint32_t;
using SDWORD = int32_t;
using WORD   = uint16_t;
using SWORD  = int16_t;
using BYTE   = uint8_t;
using SBYTE  = int8_t;
using DOUBLE = double;
using FLOAT  = float;

#define MIN_SDWORD (-2147483648)
#define MAX_SDWORD (2147483647)
#define MIN_SBYTE (-128)
#define MAX_SBYTE (127)

#define MIN_SQWORD (0x8000000000000000)
#define MAX_SQWORD (0x7FFFFFFFFFFFFFFF)

#define MAX_QWORD  (0xFFFFFFFFFFFFFFFF)
#define MAX_DWORD  (0xFFFFFFFF)
#define MAX_WORD   (0xFFFF)
#define MAX_BYTE   (0xFF)

#define MAX_DOUBLE      (1.0e+308)
#define DOUBLE_EPS      (1.0e-12)
#define MIN_DOUBLE_N    (-1.0e+308)

#define ArrayLength(a)  (sizeof(a) / sizeof(a[0]))

static inline DOUBLE MAX(DOUBLE a, DOUBLE b) { return a > b ? a : b; }
static inline QWORD MAX(QWORD a, QWORD b) { return a > b ? a : b; }
static inline DWORD MAX(DWORD a, DWORD b) { return a > b ? a : b; }
static inline SDWORD MAX(SDWORD a, SDWORD b) { return a > b ? a : b; }
static inline DOUBLE MIN(DOUBLE a, DOUBLE b) { return a < b ? a : b; }
static inline QWORD MIN(QWORD a, QWORD b) { return a < b ? a : b; }
static inline DWORD MIN(DWORD a, DWORD b) { return a < b ? a : b; }
static inline SDWORD MIN(SDWORD a, SDWORD b) { return a < b ? a : b; }

#define BYTE_BITS   (8)
#define WORD_BITS   (16)
#define DWORD_BITS  (32)
#define QWORD_BITS  (64)

static inline void inputStringSpSeparated(char *pcStr)
{
    char *pcCur = pcStr;
    for (;;) {
        char c = getchar();
        if (('\n' == c) || (EOF == c) || (' ' == c)) {
            break;
        }
        *pcCur = c;
        pcCur++;
    }
    *pcCur = '\0';
}

static inline void inputString(char *pcStr)
{
    char *pcCur = pcStr;
    for (;;) {
        char c = getchar();
        if (('\n' == c) || (EOF == c)) {
            break;
        }
        *pcCur = c;
        pcCur++;
    }
    *pcCur = '\0';
}


static inline SQWORD inputSQWORD(void)
{
    SQWORD sqNumber = 0;
    SQWORD sqMultiplier = 1;
    bool bRead = false;
    for (;;) {
        char c = getchar();
        if (!bRead) {
            if ('-' == c) {
                sqMultiplier = -1;
            }
        }
        if (('0' <= c) && (c <= '9')) {
            sqNumber *= 10LL;
            sqNumber += (SQWORD)(c - '0');
            bRead = true;
        } else {
            if (bRead) {
                return sqNumber * sqMultiplier;
            }
        }
    }
}


static inline SDWORD inputSDWORD(void)
{
    SDWORD lNumber = 0;
    SDWORD lMultiplier = 1;
    bool bRead = false;
    for (;;) {
        char c = getchar();
        if (!bRead) {
            if ('-' == c) {
                lMultiplier = -1;
            }
        }
        if (('0' <= c) && (c <= '9')) {
            lNumber *= 10;
            lNumber += (c - '0');
            bRead = true;
        } else {
            if (bRead) {
                return lNumber * lMultiplier;
            }
        }
    }
}

static inline DOUBLE inputFP(void)
{
    DOUBLE dInt = 0.0;
    DOUBLE dFrac = 0.0;
    DOUBLE dMultiplier = 1.0;
    DWORD dwFpCnt = 0;
    DOUBLE *pdCur = &dInt;
    bool bRead = false;
    for (;;) {
        char c = getchar();
        if (!bRead) {
            if ('-' == c) {
                dMultiplier = -1;
            }
        }
        if ('.' == c) {
            pdCur = &dFrac;
        } else if (('0' <= c) && (c <= '9')) {
            (*pdCur) *= 10;
            (*pdCur) += (DOUBLE)(c - '0');
            bRead = true;
            if (pdCur == &dFrac) {
                dwFpCnt++;
            }
        } else {
            if (bRead) {
                return dMultiplier * (dInt + dFrac / (pow((DOUBLE)10.0 , (DOUBLE)dwFpCnt)));
            }
        }
    }
}

/*----------------------------------------------*/
/**
 *  mod による操作ライブラリ
 */
#define ANS_MOD (1000000007)

class MODINT {
    static SQWORD MOD;
    SQWORD m_x;

public:
    MODINT(SQWORD val) {
        m_x = (val % MOD + MOD) % MOD;
    };
    MODINT() {
        m_x = 0;
    }
    static void Init(SQWORD sqMod) {
        MOD = sqMod;
    }

	MODINT& operator+= (const MODINT a)
    {
        m_x = (m_x + a.m_x) % MOD; 
        return *this;
    };
	MODINT& operator-= (const MODINT a)
    { 
        m_x = (m_x - a.m_x + MOD) % MOD; 
        return *this;
    };
	MODINT& operator*= (const MODINT a)
    {
        m_x = (m_x * a.m_x) % MOD;
        return *this;
    };
    MODINT pow(SQWORD t) const {
        if (!t) return 1;
        MODINT a = pow(t>>1);
        a *= a;
        if (t&1) a *= *this;
        return a;
    }
	MODINT operator+ (const MODINT a) const {
		MODINT res(*this);
		return (res += a);
	}
	MODINT operator- (const MODINT a) const {
		MODINT res(*this);
		return (res -= a);
	}
	MODINT operator* (const MODINT a) const {
		MODINT res(*this);
		return (res *= a);
	}
	MODINT operator/ (const MODINT a) const {
		MODINT res(*this);
		return (res /= a);
	}

    /* 逆元 */
    MODINT inv() const {
        return pow(MOD-2);
    }

    /* 除算 */
    MODINT& operator/=(const MODINT a) {
        return (*this) *= a.inv();
    } 

    /* 整数版 */
	MODINT& operator+= (const SQWORD a) {*this += MODINT(a); return *this;};
	MODINT& operator-= (const SQWORD a) {*this -= MODINT(a); return *this;};
	MODINT& operator*= (const SQWORD a) {*this *= MODINT(a); return *this;};
	MODINT& operator/= (const SQWORD a) {*this /= MODINT(a); return *this;};

    SQWORD getVal() { return m_x; };
};
SQWORD MODINT::MOD = ANS_MOD;


/*----------------------------------------------*/

/**
 *  rolling hash 
 */

#define MS  (2)
const long long mod[] = {999999937LL, 1000000007LL}, base = 9973;
struct hash_val {
    SQWORD asqHash[MS];

    const bool operator== (const hash_val &v) {
        return 0 == memcmp(this, &v, sizeof(*this));
    };
};

struct rolling_hash {
    int n;
    vector<long long> hs[MS], pw[MS];
    rolling_hash(){}
    rolling_hash(const string &s) {
        n = s.size();
        for (int i = 0; i < MS; i++) {
            hs[i].assign(n+1,0);
            pw[i].assign(n+1,0);
            hs[i][0] = 0;
            pw[i][0] = 1;
            for (int j = 0; j < n; j++) {
                pw[i][j+1] = pw[i][j]*base%mod[i];
                hs[i][j+1] = (hs[i][j]*base+s[j])%mod[i];
            }
        }
    }
    hash_val hash(int l, int r) { 
        hash_val ret;
        for (int i = 0; i < MS; i++) {
            ret.asqHash[i] = ((hs[i][r]-hs[i][l]*pw[i][r-l])%mod[i]+mod[i])%mod[i]; 
        }
        return ret;
    }

    bool match(int l1, int r1, int l2, int r2) {
        bool ret = false;
        hash_val h1 = hash(l1,r1);
        hash_val h2 = hash(l2,r2);

        return (h1 == h2);
    }

    bool match(int l, int r, hash_val h) {
        bool ret = 1;
        return (h == hash(l,r));
    }
};
/*----------------------------------------------*/
#define SQWORD_INF      (100100100100100100)
#define N_MAX_CITIES    (300)

struct EDGE_ST {
    SQWORD sqTo;
    SQWORD sqCost;

    EDGE_ST(SQWORD to, SQWORD cost) {
        sqTo = to;
        sqCost = cost;
    };
};

struct STATE_ST {
    SQWORD sqAddCnt;
    SQWORD sqRest;
};

static SQWORD s_sqL;

bool operator< (const STATE_ST &a, const STATE_ST &b) {
    if (a.sqAddCnt == b.sqAddCnt) {
        return b.sqRest < a.sqRest;
    }
    return a.sqAddCnt < b.sqAddCnt;
}

bool operator<= (const STATE_ST &a, const STATE_ST &b) {
    if (a.sqAddCnt == b.sqAddCnt) {
        return b.sqRest <= a.sqRest;
    }
    return a.sqAddCnt <= b.sqAddCnt;
}

STATE_ST operator+ (const STATE_ST &a, SQWORD b) {
    STATE_ST ret = a;
    if (ret.sqRest < b) {
        if (b <= s_sqL) {
            ret.sqRest = s_sqL - b;
            ret.sqAddCnt++;
        } else {
            ret.sqAddCnt = SQWORD_INF;
            ret.sqRest = 0;
        }
    } else {
        ret.sqRest -= b;
    }

    return ret;
}

void solveDijkstra(SQWORD sqFrom, const vector<EDGE_ST> *pvstEdges, vector<STATE_ST> &cost)
{
    typedef pair<STATE_ST, SQWORD> P;
    priority_queue<P, vector<P>, greater<P>> que;
    
    cost[sqFrom] = STATE_ST{0, s_sqL};
    que.push(P(cost[sqFrom], sqFrom));

    while (!que.empty()) {
        P p = que.top();
        que.pop();

        SDWORD v = p.second;
        if (p.first <= cost[v]) {
            for (SDWORD lIdx = 0; lIdx < pvstEdges[v].size(); lIdx++) {
                EDGE_ST e = pvstEdges[v][lIdx];

                if (cost[v] + e.sqCost < cost[e.sqTo]) {
                    cost[e.sqTo] = cost[v] + e.sqCost;
                    que.push(P(cost[e.sqTo], e.sqTo));
                }
            }
        }
    }
}


int main(void)
{
    SQWORD sqN = inputSQWORD();
    SQWORD sqM = inputSQWORD();
    s_sqL = inputSQWORD();

    vector<EDGE_ST> avecstEdge[N_MAX_CITIES + 1]; 

    for (SQWORD sqEdgeIdx = 0; sqEdgeIdx < sqM; sqEdgeIdx++) {
        SQWORD sqA = inputSQWORD();
        SQWORD sqB = inputSQWORD();
        SQWORD sqC = inputSQWORD();

        avecstEdge[sqA].emplace_back(sqB, sqC);
        avecstEdge[sqB].emplace_back(sqA, sqC);
    }

    vector<STATE_ST> vecstCost[N_MAX_CITIES + 1];
    for (SQWORD sqIdx = 0; sqIdx < N_MAX_CITIES + 1; sqIdx++) {
        vecstCost[sqIdx].resize(N_MAX_CITIES + 1, STATE_ST{SQWORD_INF, 0});
    }

    for (SQWORD sqFrom = 1; sqFrom <= sqN; sqFrom++) {
        solveDijkstra(sqFrom, avecstEdge, vecstCost[sqFrom]);
    }

    SQWORD sqQ = inputSQWORD();
    for (SQWORD sqQueryIdx = 0; sqQueryIdx < sqQ; sqQueryIdx++) {
        SQWORD sqS = inputSQWORD();
        SQWORD sqT = inputSQWORD();

        SQWORD sqAns = vecstCost[sqS][sqT].sqAddCnt;
        if (sqAns == SQWORD_INF) {
            printf("-1\n");
        } else {
            printf("%lld\n", sqAns);
        }
    }

    return 0;
}

Measured memory_bytes: 4352