quando tento instalar o npm no linux mint aparece isso

Err:1 http://sft.if.usp.br/ubuntu bionic/universe amd64 npm all 3.5.2-0ubuntu4
  Hash Sum incorreto
  Hashes of expected file:
   - SHA256:67fa27ac7a205bac1e861b92487f3e2398ab6bcc39f55741f2e1b8c09022fc77
   - SHA1:46fc13b56c4d8b25547deee9bc2db39177a75866 [weak]
   - MD5Sum:63f815dd0b8ce137b65f13616a544a77 [weak]
   - Filesize:1586014 [weak]
  Hashes of received file:
   - SHA256:d8d3bbf514e9536f87fc824feb0947ba749b7a905a3446f702d2ac5a1d523dd1
   - SHA1:e1acf0948a12805f95d6213e2cbc105ccc5d3512 [weak]
   - MD5Sum:c19a804ac1b0e474373d49614020d1da [weak]
   - Filesize:1586014 [weak]
  Last modification reported: Tue, 08 Dec 2015 15:40:28 +0000
Baixados 1.586 kB em 2s (813 kB/s)
E: Falhou ao buscar http://sft.if.usp.br/ubuntu/pool/universe/n/npm/npm_3.5.2-0ubuntu4_all.deb  Hash Sum incorreto
   Hashes of expected file:
    - SHA256:67fa27ac7a205bac1e861b92487f3e2398ab6bcc39f55741f2e1b8c09022fc77
    - SHA1:46fc13b56c4d8b25547deee9bc2db39177a75866 [weak]
    - MD5Sum:63f815dd0b8ce137b65f13616a544a77 [weak]
    - Filesize:1586014 [weak]
   Hashes of received file:
    - SHA256:d8d3bbf514e9536f87fc824feb0947ba749b7a905a3446f702d2ac5a1d523dd1
    - SHA1:e1acf0948a12805f95d6213e2cbc105ccc5d3512 [weak]
    - MD5Sum:c19a804ac1b0e474373d49614020d1da [weak]
    - Filesize:1586014 [weak]
   Last modification reported: Tue, 08 Dec 2015 15:40:28 +0000
E: Impossível buscar alguns arquivos, talvez executar apt-get update ou tentar com --fix-missing?